diff --git a/README.md b/README.md
index 490c3f20..632442f5 100644
--- a/README.md
+++ b/README.md
@@ -83,7 +83,7 @@ new OCFL repositories, but is not required when opening an existing repository.
  OCFL extension. Currently, the following extensions are implemented:
   * [0002-flat-direct-storage-layout](https://ocfl.github.io/extensions/0002-flat-direct-storage-layout.html): `FlatLayoutConfig`
   * [0003-hash-and-id-n-tuple-storage-layout](https://ocfl.github.io/extensions/0003-hash-and-id-n-tuple-storage-layout.html): `HashedNTupleIdEncapsulationLayoutConfig`
-  * [0004-hashed-n-tuple-storage-layout](https://github.com/OCFL/extensions/pull/16): `HashedNTupleLayoutConfig`
+  * [0004-hashed-n-tuple-storage-layout](https://ocfl.github.io/extensions/0004-hashed-n-tuple-storage-layout.html): `HashedNTupleLayoutConfig`
  
 ### Optional Properties
 
@@ -284,7 +284,7 @@ The following is a list of currently supported storage layout extensions:
 * [0003-hash-and-id-n-tuple-storage-layout](https://ocfl.github.io/extensions/0003-hash-and-id-n-tuple-storage-layout.html)
   * Configuration class: `HashedNTupleIdEncapsulationLayoutConfig`
   * Implementation class: `HashedNTupleIdEncapsulationLayoutExtension`
-* [0004-hashed-n-tuple-storage-layout](https://github.com/OCFL/extensions/pull/16)
+* [0004-hashed-n-tuple-storage-layout](https://ocfl.github.io/extensions/0004-hashed-n-tuple-storage-layout.html)
   * Configuration class: `HashedNTupleLayoutConfig`
   * Implementation class: `HashedNTupleLayoutExtension`
 
diff --git a/ocfl-java-api/src/main/java/edu/wisc/library/ocfl/api/OcflConstants.java b/ocfl-java-api/src/main/java/edu/wisc/library/ocfl/api/OcflConstants.java
index fbcc5145..4efe9c3d 100644
--- a/ocfl-java-api/src/main/java/edu/wisc/library/ocfl/api/OcflConstants.java
+++ b/ocfl-java-api/src/main/java/edu/wisc/library/ocfl/api/OcflConstants.java
@@ -52,7 +52,7 @@ private OcflConstants() {
     public static final DigestAlgorithm DEFAULT_DIGEST_ALGORITHM = DigestAlgorithm.sha512;
     public static final Set<DigestAlgorithm> ALLOWED_DIGEST_ALGORITHMS = Set.of(DigestAlgorithm.sha512, DigestAlgorithm.sha256);
 
-    public static final String MUTABLE_HEAD_EXT_PATH = EXTENSIONS_DIR + "/0004-mutable-head";
+    public static final String MUTABLE_HEAD_EXT_PATH = EXTENSIONS_DIR + "/0005-mutable-head";
     public static final String MUTABLE_HEAD_VERSION_PATH = MUTABLE_HEAD_EXT_PATH + "/head";
     public static final String MUTABLE_HEAD_REVISIONS_PATH = MUTABLE_HEAD_EXT_PATH + "/revisions";
 
diff --git a/ocfl-java-aws/src/main/java/edu/wisc/library/ocfl/aws/OcflS3Client.java b/ocfl-java-aws/src/main/java/edu/wisc/library/ocfl/aws/OcflS3Client.java
index 1cb0752a..c504e9d5 100644
--- a/ocfl-java-aws/src/main/java/edu/wisc/library/ocfl/aws/OcflS3Client.java
+++ b/ocfl-java-aws/src/main/java/edu/wisc/library/ocfl/aws/OcflS3Client.java
@@ -72,6 +72,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
@@ -489,6 +490,7 @@ public void deletePath(String path) {
     public void deleteObjects(Collection<String> objectPaths) {
         if (!objectPaths.isEmpty()) {
             var objectKeys = objectPaths.stream()
+                    .filter(Objects::nonNull)
                     .map(keyBuilder::buildFromPath)
                     .collect(Collectors.toList());
 
diff --git a/ocfl-java-aws/src/test/java/edu/wisc/library/ocfl/aws/OcflS3Test.java b/ocfl-java-aws/src/test/java/edu/wisc/library/ocfl/aws/OcflS3Test.java
index 9f51fafe..65bbf71b 100644
--- a/ocfl-java-aws/src/test/java/edu/wisc/library/ocfl/aws/OcflS3Test.java
+++ b/ocfl-java-aws/src/test/java/edu/wisc/library/ocfl/aws/OcflS3Test.java
@@ -67,12 +67,12 @@ public void basicMutableHeadTest(String repoPrefix) {
                 "inventory.json.sha512",
                 "v1/inventory.json",
                 "v1/inventory.json.sha512",
-                "extensions/0004-mutable-head/root-inventory.json.sha512",
-                "extensions/0004-mutable-head/revisions/r1",
-                "extensions/0004-mutable-head/head/inventory.json",
-                "extensions/0004-mutable-head/head/inventory.json.sha512",
-                "extensions/0004-mutable-head/head/content/r1/dir/file1.txt",
-                "extensions/0004-mutable-head/head/content/r1/dir/sub/file2.txt"
+                "extensions/0005-mutable-head/root-inventory.json.sha512",
+                "extensions/0005-mutable-head/revisions/r1",
+                "extensions/0005-mutable-head/head/inventory.json",
+                "extensions/0005-mutable-head/head/inventory.json.sha512",
+                "extensions/0005-mutable-head/head/content/r1/dir/file1.txt",
+                "extensions/0005-mutable-head/head/content/r1/dir/sub/file2.txt"
         ));
 
         assertEquals("file1", streamToString(repo.getObject(ObjectVersionId.head(objectId)).getFile("dir/file1.txt").getStream()));
diff --git a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/HashedNTupleLayoutExtension.java b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/HashedNTupleLayoutExtension.java
index bd7dcdfd..7888ef9e 100644
--- a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/HashedNTupleLayoutExtension.java
+++ b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/HashedNTupleLayoutExtension.java
@@ -31,9 +31,8 @@
 import edu.wisc.library.ocfl.core.util.DigestUtil;
 
 /**
- * Implementation of the Hashed Truncated N-tuple Trees for OCFL Storage Hierarchies extension.
- *
- * TODO add link to spec when finalized
+ * Implementation of the <a href="https://ocfl.github.io/extensions/0004-hashed-n-tuple-storage-layout.html">
+ * Hashed N-tuple Storage Layout</a> extension.
  */
 public class HashedNTupleLayoutExtension implements OcflStorageLayoutExtension {
 
diff --git a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/FlatLayoutConfig.java b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/FlatLayoutConfig.java
index 0d8d7895..e7e83579 100644
--- a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/FlatLayoutConfig.java
+++ b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/FlatLayoutConfig.java
@@ -31,9 +31,8 @@
 import java.util.Objects;
 
 /**
- * Configuration for the Flat Storage Layout extension.
- *
- * TODO Add link to spec when finalized
+ * Configuration for the <a href="https://ocfl.github.io/extensions/0002-flat-direct-storage-layout.html">
+ * Flat Direct Storage Layout</a> extension.
  */
 public class FlatLayoutConfig implements OcflExtensionConfig {
 
diff --git a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/HashedNTupleLayoutConfig.java b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/HashedNTupleLayoutConfig.java
index 77431411..9a85c1da 100644
--- a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/HashedNTupleLayoutConfig.java
+++ b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/extension/storage/layout/config/HashedNTupleLayoutConfig.java
@@ -35,9 +35,8 @@
 import java.util.Objects;
 
 /**
- * Configuration for the Hashed Truncated N-tuple Trees for OCFL Storage Hierarchies extension.
- *
- * TODO Add link to spec when finalized
+ * Configuration for the <a href="https://ocfl.github.io/extensions/0004-hashed-n-tuple-storage-layout.html">
+ * Hashed N-tuple Storage Layout</a> extension.
  */
 public class HashedNTupleLayoutConfig implements OcflExtensionConfig {
 
diff --git a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/cloud/CloudOcflStorageInitializer.java b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/cloud/CloudOcflStorageInitializer.java
index 1350d0d1..9a20e7c4 100644
--- a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/cloud/CloudOcflStorageInitializer.java
+++ b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/cloud/CloudOcflStorageInitializer.java
@@ -58,6 +58,7 @@ public class CloudOcflStorageInitializer {
 
     private static final Logger LOG = LoggerFactory.getLogger(CloudOcflStorageInitializer.class);
 
+    private static final String SPECS_DIR = "specs/";
     private static final String MEDIA_TYPE_TEXT = "text/plain; charset=UTF-8";
     private static final String MEDIA_TYPE_JSON = "application/json; charset=UTF-8";
     private static final String OBJECT_MARKER_PREFIX = "0=ocfl_object";
@@ -209,6 +210,7 @@ private OcflStorageLayoutExtension initNewRepo(OcflVersion ocflVersion, OcflExte
             keys.add(writeNamasteFile(ocflVersion));
             keys.add(writeOcflSpec(ocflVersion));
             keys.addAll(writeOcflLayout(layoutConfig, layoutExtension.getDescription()));
+            keys.add(writeOcflLayoutSpec(layoutConfig));
             return layoutExtension;
         } catch (RuntimeException e) {
             LOG.error("Failed to initialize OCFL repository", e);
@@ -218,9 +220,21 @@ private OcflStorageLayoutExtension initNewRepo(OcflVersion ocflVersion, OcflExte
     }
 
     private String writeOcflSpec(OcflVersion ocflVersion) {
-        var ocflSpecFile = ocflVersion.getOcflVersion() + ".txt";
-        try (var ocflSpecStream = this.getClass().getClassLoader().getResourceAsStream(ocflSpecFile)) {
-            return uploadStream(ocflSpecFile, ocflSpecStream).getPath();
+        return writeSpecFile(ocflVersion.getOcflVersion() + ".txt");
+    }
+
+    private String writeOcflLayoutSpec(OcflExtensionConfig layoutConfig) {
+        try {
+            return writeSpecFile(layoutConfig.getExtensionName() + ".md");
+        } catch (RuntimeException e) {
+            LOG.warn("Failed to write spec file for layout extension {}", layoutConfig.getExtensionName(), e);
+            return null;
+        }
+    }
+
+    private String writeSpecFile(String fileName) {
+        try (var stream = this.getClass().getClassLoader().getResourceAsStream(SPECS_DIR + fileName)) {
+            return uploadStream(fileName, stream).getPath();
         } catch (IOException e) {
             throw new OcflIOException(e);
         }
diff --git a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializer.java b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializer.java
index ed5d0fc9..cb01e2a0 100644
--- a/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializer.java
+++ b/ocfl-java-core/src/main/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializer.java
@@ -60,6 +60,7 @@ public class FileSystemOcflStorageInitializer {
 
     private static final Logger LOG = LoggerFactory.getLogger(FileSystemOcflStorageInitializer.class);
 
+    private static final String SPECS_DIR = "specs/";
     private static final String OBJECT_MARKER_PREFIX = "0=ocfl_object";
 
     private final ObjectMapper objectMapper;
@@ -222,6 +223,7 @@ private OcflStorageLayoutExtension initNewRepo(Path repositoryRoot, OcflVersion
             new NamasteTypeFile(ocflVersion.getOcflVersion()).writeFile(repositoryRoot);
             writeOcflSpec(repositoryRoot, ocflVersion);
             writeOcflLayout(repositoryRoot, layoutConfig, layoutExtension.getDescription());
+            writeOcflLayoutSpec(repositoryRoot, layoutConfig);
             return layoutExtension;
         } catch (RuntimeException e) {
             LOG.error("Failed to initialize OCFL repository at {}", repositoryRoot, e);
@@ -232,8 +234,21 @@ private OcflStorageLayoutExtension initNewRepo(Path repositoryRoot, OcflVersion
 
     private void writeOcflSpec(Path repositoryRoot, OcflVersion ocflVersion) {
         var ocflSpecFile = ocflVersion.getOcflVersion() + ".txt";
-        try (var ocflSpecStream = this.getClass().getClassLoader().getResourceAsStream(ocflSpecFile)) {
-            Files.copy(ocflSpecStream, repositoryRoot.resolve(ocflSpecFile));
+        writeSpecFile(repositoryRoot, ocflSpecFile);
+    }
+
+    private void writeOcflLayoutSpec(Path repositoryRoot, OcflExtensionConfig layoutConfig) {
+        var specFile = layoutConfig.getExtensionName() + ".md";
+        try {
+            writeSpecFile(repositoryRoot, specFile);
+        } catch (RuntimeException e) {
+            LOG.warn("Failed to write spec file for layout extension {}", layoutConfig.getExtensionName(), e);
+        }
+    }
+
+    private void writeSpecFile(Path repositoryRoot, String fileName) {
+        try (var stream = this.getClass().getClassLoader().getResourceAsStream(SPECS_DIR + fileName)) {
+            Files.copy(stream, repositoryRoot.resolve(fileName));
         } catch (IOException e) {
             throw new OcflIOException(e);
         }
diff --git a/ocfl-java-core/src/main/resources/specs/0002-flat-direct-storage-layout.md b/ocfl-java-core/src/main/resources/specs/0002-flat-direct-storage-layout.md
new file mode 100644
index 00000000..5acd6a68
--- /dev/null
+++ b/ocfl-java-core/src/main/resources/specs/0002-flat-direct-storage-layout.md
@@ -0,0 +1,69 @@
+# OCFL Community Extension 0002: Flat Direct Storage Layout
+
+* **Extension Name:** 0002-flat-direct-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes a simple flat OCFL storage layout. OCFL object identifiers are mapped directly to directory names that are direct children of the OCFL storage root directory.
+
+The limitations of this layout are filesystem dependent, but are generally as follows:
+
+* The size of object IDs cannot exceed the maximum allowed directory name size (eg. 255 characters)
+* Object IDs cannot include characters that are illegal in directory names
+* Performance may degrade as the size of a repository increases because every object is a direct child of the storage root
+
+## Parameters
+
+This extension has no parameters.
+
+## Procedure
+
+The OCFL object identifier is used, without any changes, as the object's root path within the OCFL storage root.
+
+## Examples
+
+### Example 1
+
+This example demonstrates some mappings that produce directory names that are valid on unix filesystems.
+
+#### Mappings
+
+| Object ID | Object Root Path |
+| --- | --- |
+| object-01 | `object-01` |
+| ..hor\_rib:lé-$id | `..hor_rib:lé-$id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── object-01/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── ..hor_rib:lé-$id/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates some mappings that produce directory names that are invalid on unix filesystems; therefore this layout cannot be used in a repository that needs to be able to store objects with IDs like these.
+
+#### Mappings
+
+| Object ID | Object Root Path |
+| --- | --- |
+| info:fedora/object-01 | `info:fedora/object-01` |
+| abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij | `abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij` |
+
diff --git a/ocfl-java-core/src/main/resources/specs/0003-hash-and-id-n-tuple-storage-layout.md b/ocfl-java-core/src/main/resources/specs/0003-hash-and-id-n-tuple-storage-layout.md
new file mode 100644
index 00000000..85095f75
--- /dev/null
+++ b/ocfl-java-core/src/main/resources/specs/0003-hash-and-id-n-tuple-storage-layout.md
@@ -0,0 +1,380 @@
+# OCFL Community Extension 0003: Hashed Truncated N-tuple Trees with Object ID Encapsulating Directory for OCFL Storage Hierarchies
+
+* **Extension Name:** 0003-hash-and-id-n-tuple-storage-layout
+* **Authors:** Ben Cail
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters, to OCFL object root directories.
+
+Using this extension, OCFL object identifiers are hashed and encoded as hex
+strings (all letters lower-case). These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL storage
+root. Finally, the OCFL object identifier is percent-encoded to create a
+directory name for the OCFL object root (see ["Encapsulation
+Directory"](#encapsulation-directory) section below).
+
+The n-tuple segments approach allows OCFL object identifiers to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. The encoded encapsulation directory name provides visibility into
+the object identifier from the file path (see ["Encapsulation
+Directory"](#encapsulation-directory) section below for details).
+
+## Encapsulation Directory
+
+For basic OCFL object identifiers, the object identifier is used as the name of
+the encapsulation directory (ie. the object root directory).
+
+Some object identifiers could contain characters that are not safe for directory
+names on all filesystems. Safe characters are defined as A-Z, a-z, 0-9, '-' and
+'\_'. When an unsafe character is encountered in an object identifier, it is
+percent-encoded using the lower-case hex characters of its UTF-8 encoding.
+
+Some object identifiers could also result in an encoded string that is longer
+than can be supported as a directory name. To handle that scenario, if the
+percent-encoded object identifier is longer than 100 characters, it is truncated
+to 100 characters, and then the digest of the original object identifier is
+appended to the encoded object identifier like this:
+\<encoded-object-identifier-first-100-chars>-\<digest>. Note: this means that it
+is no longer possible to determine the full object identifier from the
+encapsulation directory name - some characters have been removed, and even the
+first 100 characters of the encoded object identifier cannot be fully, reliably
+decoded, because the truncation may leave a partial encoding at the end of the
+100 characters.
+
+| Object ID | Encapsulation Directory Name |
+| --- | --- |
+| object-01 | object-01 |
+| ..Hor/rib:lè-$id | %2e%2eHor%2frib%3al%c3%a8-%24id |
+| abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghija | abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220 |
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply to the OCFL object identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the size of the segments (in characters) that the digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates how many segments are used for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in each tuple.
+The tuples are used as directory names. The default value is `3`, which means
+that each intermediate directory in the OCFL storage hierarchy could contain up
+to 4096 directories. Increasing this value increases the maximum number of
+sub-directories per directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+## Procedure
+
+The following is an outline of the steps to follow to map an OCFL object
+identifier to an OCFL object root path using this extension (also see the
+["Python Code"](#python-code) section):
+
+1. The OCFL object identifier is encoded as UTF-8 and hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lower-case hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. The OCFL object identifier is percent-encoded to create the encapsulation
+   directory name (see ["Encapsulation Directory"](#encapsulation-directory)
+   section above for details).
+6. The encapsulation directory name is joined to the end of the path.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+this extension's default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/object-01` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── object-01/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── %2e%2ehor%2frib%3ale-%24id/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgorithm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── %2e%2ehor%2frib%3ale-%24id/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── object-01/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `object-id` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── object-id/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── %2e%2ehor%2frib%3ale-%24id/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
+
+## Python Code
+
+Here is some python code that implements the algorithm:
+
+```
+import codecs
+import hashlib
+import os
+import re
+
+
+def _percent_encode(c):
+    c_bytes = c.encode('utf8')
+    s = ''
+    for b in c_bytes:
+        s += '%' + codecs.encode(bytes([b]), encoding='hex_codec').decode('utf8')
+    return s
+
+
+def _get_encapsulation_directory(object_id, digest):
+    d = ''
+    for c in object_id:
+        if re.match(r'[A-Za-z0-9-_]{1}', c):
+            d += c
+        else:
+            d += _percent_encode(c)
+    if len(d) > 100:
+        return f'{d[:100]}-{digest}'
+    return d
+
+
+def ocfl_path(object_id, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    object_id_utf8 = object_id.encode('utf8')
+    if algorithm == 'md5':
+        digest = hashlib.md5(object_id_utf8).hexdigest()
+    elif algorithm == 'sha256':
+        digest = hashlib.sha256(object_id_utf8).hexdigest()
+    elif algorithm == 'sha512':
+        digest = hashlib.sha512(object_id_utf8).hexdigest()
+    digest = digest.lower()
+    path = ''
+    for i in range(number_of_tuples):
+        part = digest[i*tuple_size:i*tuple_size+tuple_size]
+        path = os.path.join(path, part)
+    encapsulation_directory = _get_encapsulation_directory(object_id, digest=digest)
+    path = os.path.join(path, encapsulation_directory)
+    return path
+
+
+def _check_path(object_id, correct_path, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    p = ocfl_path(object_id, algorithm=algorithm, tuple_size=tuple_size, number_of_tuples=number_of_tuples)
+    assert p == correct_path, f'{p} != {correct_path}'
+    print(f'  "{object_id}" {algorithm} => {p}')
+
+
+def run_tests():
+    print('running tests...')
+    assert _percent_encode('.') == '%2e'
+    assert _percent_encode('ç') == '%c3%a7'
+    _check_path(object_id='object-01', correct_path='3c0/ff4/240/object-01')
+    _check_path(object_id='object-01', correct_path='ff7/553/449/object-01', algorithm='md5')
+    _check_path(object_id='object-01', correct_path='ff755/34492/object-01', algorithm='md5', tuple_size=5, number_of_tuples=2)
+    _check_path(object_id='object-01', correct_path='object-01', algorithm='md5', tuple_size=0, number_of_tuples=0)
+    _check_path(object_id='object-01', correct_path='ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01', algorithm='md5', tuple_size=2, number_of_tuples=15)
+    _check_path(object_id='..hor/rib:le-$id', correct_path='487/326/d8c/%2e%2ehor%2frib%3ale-%24id')
+    _check_path(object_id='..hor/rib:le-$id', correct_path='083/197/66f/%2e%2ehor%2frib%3ale-%24id', algorithm='md5') #08319766fb6c2935dd175b94267717e0
+    _check_path(object_id='..Hor/rib:lè-$id', correct_path='373/529/21a/%2e%2eHor%2frib%3al%c3%a8-%24id')
+    long_object_id = 'abcdefghij' * 26
+    long_object_id_digest = '55b432806f4e270da0cf23815ed338742179002153cd8d896f23b3e2d8a14359'
+    _check_path(object_id=long_object_id, correct_path=f'55b/432/806/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_digest}')
+    long_object_id_101 = 'abcdefghij' * 10 + 'a'
+    long_object_id_101_digest = '5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220'
+    _check_path(object_id=long_object_id_101, correct_path=f'5cc/73e/648/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_101_digest}')
+
+
+if __name__ == '__main__':
+    run_tests()
+```
diff --git a/ocfl-java-core/src/main/resources/specs/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-core/src/main/resources/specs/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-core/src/main/resources/specs/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-core/src/main/resources/ocfl_1.0.txt b/ocfl-java-core/src/main/resources/specs/ocfl_1.0.txt
similarity index 100%
rename from ocfl-java-core/src/main/resources/ocfl_1.0.txt
rename to ocfl-java-core/src/main/resources/specs/ocfl_1.0.txt
diff --git a/ocfl-java-core/src/test/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializerTest.java b/ocfl-java-core/src/test/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializerTest.java
index 9c543111..c0d21ba3 100644
--- a/ocfl-java-core/src/test/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializerTest.java
+++ b/ocfl-java-core/src/test/java/edu/wisc/library/ocfl/core/storage/filesystem/FileSystemOcflStorageInitializerTest.java
@@ -145,6 +145,7 @@ private void assertRootHasFiles(Path root) {
                 aFileNamed(equalTo("0=ocfl_1.0")),
                 aFileNamed(equalTo("ocfl_1.0.txt")),
                 aFileNamed(equalTo(OcflConstants.OCFL_LAYOUT)),
+                aFileNamed(equalTo(HashedNTupleLayoutExtension.EXTENSION_NAME + ".md")),
                 aFileNamed(equalTo(OcflConstants.EXTENSIONS_DIR))));
         assertThat(root.resolve(OcflConstants.EXTENSIONS_DIR)
                 .resolve(HashedNTupleLayoutExtension.EXTENSION_NAME)
diff --git a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/MutableHeadITest.java b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/MutableHeadITest.java
index b2a2a177..a14b8008 100644
--- a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/MutableHeadITest.java
+++ b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/MutableHeadITest.java
@@ -266,7 +266,7 @@ public void shouldFailWhenRevisionMarkerAlreadyExists() {
 
         OcflAsserts.assertThrowsWithMessage(ObjectOutOfSyncException.class, "Changes are out of sync with the current object state", () -> {
             repo.stageChanges(ObjectVersionId.head(objectId), defaultVersionInfo.setMessage("stage 2"), updater -> {
-                writeFile(repoName, O1_PATH + "/extensions/0004-mutable-head/revisions/r2", TestHelper.inputStream("r2"));
+                writeFile(repoName, O1_PATH + "/extensions/0005-mutable-head/revisions/r2", TestHelper.inputStream("r2"));
                 updater.writeFile(new ByteArrayInputStream("file5" .getBytes()), "file5")
                         .renameFile("dir1/file3", "file3")
                         .removeFile("dir1/file4");
@@ -416,7 +416,7 @@ public void rejectImportObjectWhenWithMutableHeadWhenInvalidMutableHead() throws
 
         repo1.exportObject(objectId, output);
 
-        Files.delete(output.resolve("extensions/0004-mutable-head/head/content/r1/dir1/file3"));
+        Files.delete(output.resolve("extensions/0005-mutable-head/head/content/r1/dir1/file3"));
 
         var repoName2 = "mutable-import";
         var repo2 = defaultRepo(repoName2);
diff --git a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/OcflITest.java b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/OcflITest.java
index 3910a6d7..3b4fc0b5 100644
--- a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/OcflITest.java
+++ b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/OcflITest.java
@@ -1119,7 +1119,7 @@ public void purgeObjectWhenExists() {
             repo.describeObject(objectId);
         });
 
-        assertEquals(4, listFilesInRepo(repoName).size());
+        assertEquals(5, listFilesInRepo(repoName).size());
     }
 
     @Test
@@ -1139,7 +1139,7 @@ public void purgeObjectDoNothingWhenDoesNotExist() {
             repo.describeObject("o4");
         });
 
-        assertEquals(11, listFilesInRepo(repoName).size());
+        assertEquals(12, listFilesInRepo(repoName).size());
     }
 
     @Test
diff --git a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/filesystem/FileSystemOcflITest.java b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/filesystem/FileSystemOcflITest.java
index 47504bea..7b186bb2 100644
--- a/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/filesystem/FileSystemOcflITest.java
+++ b/ocfl-java-itest/src/test/java/edu/wisc/library/ocfl/itest/filesystem/FileSystemOcflITest.java
@@ -5,6 +5,7 @@
 import edu.wisc.library.ocfl.api.model.ObjectVersionId;
 import edu.wisc.library.ocfl.core.OcflRepositoryBuilder;
 import edu.wisc.library.ocfl.core.cache.NoOpCache;
+import edu.wisc.library.ocfl.core.extension.storage.layout.HashedNTupleLayoutExtension;
 import edu.wisc.library.ocfl.core.extension.storage.layout.config.HashedNTupleIdEncapsulationLayoutConfig;
 import edu.wisc.library.ocfl.core.extension.storage.layout.config.HashedNTupleLayoutConfig;
 import edu.wisc.library.ocfl.core.util.FileUtil;
@@ -86,7 +87,9 @@ public void purgeShouldRemoveEmptyParentDirs() throws IOException {
         repo.purgeObject(objectId);
 
         assertThat(Arrays.asList(repoDir(repoName).toFile().list()).stream().collect(Collectors.toList()),
-                containsInAnyOrder("0=ocfl_1.0", "ocfl_1.0.txt", OcflConstants.EXTENSIONS_DIR, OcflConstants.OCFL_LAYOUT));
+                containsInAnyOrder("0=ocfl_1.0", "ocfl_1.0.txt",
+                        OcflConstants.EXTENSIONS_DIR, OcflConstants.OCFL_LAYOUT,
+                        HashedNTupleLayoutExtension.EXTENSION_NAME + ".md"));
     }
 
     @Override
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/different-content/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/different-content/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/different-content/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/different-digest/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/different-digest/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/different-digest/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/flat-layout/0002-flat-direct-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/flat-layout/0002-flat-direct-storage-layout.md
new file mode 100644
index 00000000..5acd6a68
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/flat-layout/0002-flat-direct-storage-layout.md
@@ -0,0 +1,69 @@
+# OCFL Community Extension 0002: Flat Direct Storage Layout
+
+* **Extension Name:** 0002-flat-direct-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes a simple flat OCFL storage layout. OCFL object identifiers are mapped directly to directory names that are direct children of the OCFL storage root directory.
+
+The limitations of this layout are filesystem dependent, but are generally as follows:
+
+* The size of object IDs cannot exceed the maximum allowed directory name size (eg. 255 characters)
+* Object IDs cannot include characters that are illegal in directory names
+* Performance may degrade as the size of a repository increases because every object is a direct child of the storage root
+
+## Parameters
+
+This extension has no parameters.
+
+## Procedure
+
+The OCFL object identifier is used, without any changes, as the object's root path within the OCFL storage root.
+
+## Examples
+
+### Example 1
+
+This example demonstrates some mappings that produce directory names that are valid on unix filesystems.
+
+#### Mappings
+
+| Object ID | Object Root Path |
+| --- | --- |
+| object-01 | `object-01` |
+| ..hor\_rib:lé-$id | `..hor_rib:lé-$id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── object-01/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── ..hor_rib:lé-$id/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates some mappings that produce directory names that are invalid on unix filesystems; therefore this layout cannot be used in a repository that needs to be able to store objects with IDs like these.
+
+#### Mappings
+
+| Object ID | Object Root Path |
+| --- | --- |
+| info:fedora/object-01 | `info:fedora/object-01` |
+| abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij | `abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij` |
+
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout-2/0003-hash-and-id-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout-2/0003-hash-and-id-n-tuple-storage-layout.md
new file mode 100644
index 00000000..85095f75
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout-2/0003-hash-and-id-n-tuple-storage-layout.md
@@ -0,0 +1,380 @@
+# OCFL Community Extension 0003: Hashed Truncated N-tuple Trees with Object ID Encapsulating Directory for OCFL Storage Hierarchies
+
+* **Extension Name:** 0003-hash-and-id-n-tuple-storage-layout
+* **Authors:** Ben Cail
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters, to OCFL object root directories.
+
+Using this extension, OCFL object identifiers are hashed and encoded as hex
+strings (all letters lower-case). These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL storage
+root. Finally, the OCFL object identifier is percent-encoded to create a
+directory name for the OCFL object root (see ["Encapsulation
+Directory"](#encapsulation-directory) section below).
+
+The n-tuple segments approach allows OCFL object identifiers to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. The encoded encapsulation directory name provides visibility into
+the object identifier from the file path (see ["Encapsulation
+Directory"](#encapsulation-directory) section below for details).
+
+## Encapsulation Directory
+
+For basic OCFL object identifiers, the object identifier is used as the name of
+the encapsulation directory (ie. the object root directory).
+
+Some object identifiers could contain characters that are not safe for directory
+names on all filesystems. Safe characters are defined as A-Z, a-z, 0-9, '-' and
+'\_'. When an unsafe character is encountered in an object identifier, it is
+percent-encoded using the lower-case hex characters of its UTF-8 encoding.
+
+Some object identifiers could also result in an encoded string that is longer
+than can be supported as a directory name. To handle that scenario, if the
+percent-encoded object identifier is longer than 100 characters, it is truncated
+to 100 characters, and then the digest of the original object identifier is
+appended to the encoded object identifier like this:
+\<encoded-object-identifier-first-100-chars>-\<digest>. Note: this means that it
+is no longer possible to determine the full object identifier from the
+encapsulation directory name - some characters have been removed, and even the
+first 100 characters of the encoded object identifier cannot be fully, reliably
+decoded, because the truncation may leave a partial encoding at the end of the
+100 characters.
+
+| Object ID | Encapsulation Directory Name |
+| --- | --- |
+| object-01 | object-01 |
+| ..Hor/rib:lè-$id | %2e%2eHor%2frib%3al%c3%a8-%24id |
+| abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghija | abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220 |
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply to the OCFL object identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the size of the segments (in characters) that the digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates how many segments are used for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in each tuple.
+The tuples are used as directory names. The default value is `3`, which means
+that each intermediate directory in the OCFL storage hierarchy could contain up
+to 4096 directories. Increasing this value increases the maximum number of
+sub-directories per directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+## Procedure
+
+The following is an outline of the steps to follow to map an OCFL object
+identifier to an OCFL object root path using this extension (also see the
+["Python Code"](#python-code) section):
+
+1. The OCFL object identifier is encoded as UTF-8 and hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lower-case hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. The OCFL object identifier is percent-encoded to create the encapsulation
+   directory name (see ["Encapsulation Directory"](#encapsulation-directory)
+   section above for details).
+6. The encapsulation directory name is joined to the end of the path.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+this extension's default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/object-01` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── object-01/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── %2e%2ehor%2frib%3ale-%24id/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgorithm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── %2e%2ehor%2frib%3ale-%24id/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── object-01/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `object-id` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── object-id/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── %2e%2ehor%2frib%3ale-%24id/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
+
+## Python Code
+
+Here is some python code that implements the algorithm:
+
+```
+import codecs
+import hashlib
+import os
+import re
+
+
+def _percent_encode(c):
+    c_bytes = c.encode('utf8')
+    s = ''
+    for b in c_bytes:
+        s += '%' + codecs.encode(bytes([b]), encoding='hex_codec').decode('utf8')
+    return s
+
+
+def _get_encapsulation_directory(object_id, digest):
+    d = ''
+    for c in object_id:
+        if re.match(r'[A-Za-z0-9-_]{1}', c):
+            d += c
+        else:
+            d += _percent_encode(c)
+    if len(d) > 100:
+        return f'{d[:100]}-{digest}'
+    return d
+
+
+def ocfl_path(object_id, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    object_id_utf8 = object_id.encode('utf8')
+    if algorithm == 'md5':
+        digest = hashlib.md5(object_id_utf8).hexdigest()
+    elif algorithm == 'sha256':
+        digest = hashlib.sha256(object_id_utf8).hexdigest()
+    elif algorithm == 'sha512':
+        digest = hashlib.sha512(object_id_utf8).hexdigest()
+    digest = digest.lower()
+    path = ''
+    for i in range(number_of_tuples):
+        part = digest[i*tuple_size:i*tuple_size+tuple_size]
+        path = os.path.join(path, part)
+    encapsulation_directory = _get_encapsulation_directory(object_id, digest=digest)
+    path = os.path.join(path, encapsulation_directory)
+    return path
+
+
+def _check_path(object_id, correct_path, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    p = ocfl_path(object_id, algorithm=algorithm, tuple_size=tuple_size, number_of_tuples=number_of_tuples)
+    assert p == correct_path, f'{p} != {correct_path}'
+    print(f'  "{object_id}" {algorithm} => {p}')
+
+
+def run_tests():
+    print('running tests...')
+    assert _percent_encode('.') == '%2e'
+    assert _percent_encode('ç') == '%c3%a7'
+    _check_path(object_id='object-01', correct_path='3c0/ff4/240/object-01')
+    _check_path(object_id='object-01', correct_path='ff7/553/449/object-01', algorithm='md5')
+    _check_path(object_id='object-01', correct_path='ff755/34492/object-01', algorithm='md5', tuple_size=5, number_of_tuples=2)
+    _check_path(object_id='object-01', correct_path='object-01', algorithm='md5', tuple_size=0, number_of_tuples=0)
+    _check_path(object_id='object-01', correct_path='ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01', algorithm='md5', tuple_size=2, number_of_tuples=15)
+    _check_path(object_id='..hor/rib:le-$id', correct_path='487/326/d8c/%2e%2ehor%2frib%3ale-%24id')
+    _check_path(object_id='..hor/rib:le-$id', correct_path='083/197/66f/%2e%2ehor%2frib%3ale-%24id', algorithm='md5') #08319766fb6c2935dd175b94267717e0
+    _check_path(object_id='..Hor/rib:lè-$id', correct_path='373/529/21a/%2e%2eHor%2frib%3al%c3%a8-%24id')
+    long_object_id = 'abcdefghij' * 26
+    long_object_id_digest = '55b432806f4e270da0cf23815ed338742179002153cd8d896f23b3e2d8a14359'
+    _check_path(object_id=long_object_id, correct_path=f'55b/432/806/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_digest}')
+    long_object_id_101 = 'abcdefghij' * 10 + 'a'
+    long_object_id_101_digest = '5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220'
+    _check_path(object_id=long_object_id_101, correct_path=f'5cc/73e/648/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_101_digest}')
+
+
+if __name__ == '__main__':
+    run_tests()
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout/0003-hash-and-id-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout/0003-hash-and-id-n-tuple-storage-layout.md
new file mode 100644
index 00000000..85095f75
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/hashed-id-layout/0003-hash-and-id-n-tuple-storage-layout.md
@@ -0,0 +1,380 @@
+# OCFL Community Extension 0003: Hashed Truncated N-tuple Trees with Object ID Encapsulating Directory for OCFL Storage Hierarchies
+
+* **Extension Name:** 0003-hash-and-id-n-tuple-storage-layout
+* **Authors:** Ben Cail
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters, to OCFL object root directories.
+
+Using this extension, OCFL object identifiers are hashed and encoded as hex
+strings (all letters lower-case). These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL storage
+root. Finally, the OCFL object identifier is percent-encoded to create a
+directory name for the OCFL object root (see ["Encapsulation
+Directory"](#encapsulation-directory) section below).
+
+The n-tuple segments approach allows OCFL object identifiers to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. The encoded encapsulation directory name provides visibility into
+the object identifier from the file path (see ["Encapsulation
+Directory"](#encapsulation-directory) section below for details).
+
+## Encapsulation Directory
+
+For basic OCFL object identifiers, the object identifier is used as the name of
+the encapsulation directory (ie. the object root directory).
+
+Some object identifiers could contain characters that are not safe for directory
+names on all filesystems. Safe characters are defined as A-Z, a-z, 0-9, '-' and
+'\_'. When an unsafe character is encountered in an object identifier, it is
+percent-encoded using the lower-case hex characters of its UTF-8 encoding.
+
+Some object identifiers could also result in an encoded string that is longer
+than can be supported as a directory name. To handle that scenario, if the
+percent-encoded object identifier is longer than 100 characters, it is truncated
+to 100 characters, and then the digest of the original object identifier is
+appended to the encoded object identifier like this:
+\<encoded-object-identifier-first-100-chars>-\<digest>. Note: this means that it
+is no longer possible to determine the full object identifier from the
+encapsulation directory name - some characters have been removed, and even the
+first 100 characters of the encoded object identifier cannot be fully, reliably
+decoded, because the truncation may leave a partial encoding at the end of the
+100 characters.
+
+| Object ID | Encapsulation Directory Name |
+| --- | --- |
+| object-01 | object-01 |
+| ..Hor/rib:lè-$id | %2e%2eHor%2frib%3al%c3%a8-%24id |
+| abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghija | abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220 |
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply to the OCFL object identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the size of the segments (in characters) that the digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates how many segments are used for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in each tuple.
+The tuples are used as directory names. The default value is `3`, which means
+that each intermediate directory in the OCFL storage hierarchy could contain up
+to 4096 directories. Increasing this value increases the maximum number of
+sub-directories per directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+## Procedure
+
+The following is an outline of the steps to follow to map an OCFL object
+identifier to an OCFL object root path using this extension (also see the
+["Python Code"](#python-code) section):
+
+1. The OCFL object identifier is encoded as UTF-8 and hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lower-case hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. The OCFL object identifier is percent-encoded to create the encapsulation
+   directory name (see ["Encapsulation Directory"](#encapsulation-directory)
+   section above for details).
+6. The encapsulation directory name is joined to the end of the path.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+this extension's default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/object-01` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── object-01/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── %2e%2ehor%2frib%3ale-%24id/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgorithm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── %2e%2ehor%2frib%3ale-%24id/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── object-01/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0003-hash-and-id-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --- | --- | --- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `object-id` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `%2e%2ehor%2frib%3ale-%24id` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
+├── object-id/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── %2e%2ehor%2frib%3ale-%24id/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
+
+## Python Code
+
+Here is some python code that implements the algorithm:
+
+```
+import codecs
+import hashlib
+import os
+import re
+
+
+def _percent_encode(c):
+    c_bytes = c.encode('utf8')
+    s = ''
+    for b in c_bytes:
+        s += '%' + codecs.encode(bytes([b]), encoding='hex_codec').decode('utf8')
+    return s
+
+
+def _get_encapsulation_directory(object_id, digest):
+    d = ''
+    for c in object_id:
+        if re.match(r'[A-Za-z0-9-_]{1}', c):
+            d += c
+        else:
+            d += _percent_encode(c)
+    if len(d) > 100:
+        return f'{d[:100]}-{digest}'
+    return d
+
+
+def ocfl_path(object_id, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    object_id_utf8 = object_id.encode('utf8')
+    if algorithm == 'md5':
+        digest = hashlib.md5(object_id_utf8).hexdigest()
+    elif algorithm == 'sha256':
+        digest = hashlib.sha256(object_id_utf8).hexdigest()
+    elif algorithm == 'sha512':
+        digest = hashlib.sha512(object_id_utf8).hexdigest()
+    digest = digest.lower()
+    path = ''
+    for i in range(number_of_tuples):
+        part = digest[i*tuple_size:i*tuple_size+tuple_size]
+        path = os.path.join(path, part)
+    encapsulation_directory = _get_encapsulation_directory(object_id, digest=digest)
+    path = os.path.join(path, encapsulation_directory)
+    return path
+
+
+def _check_path(object_id, correct_path, algorithm='sha256', tuple_size=3, number_of_tuples=3):
+    p = ocfl_path(object_id, algorithm=algorithm, tuple_size=tuple_size, number_of_tuples=number_of_tuples)
+    assert p == correct_path, f'{p} != {correct_path}'
+    print(f'  "{object_id}" {algorithm} => {p}')
+
+
+def run_tests():
+    print('running tests...')
+    assert _percent_encode('.') == '%2e'
+    assert _percent_encode('ç') == '%c3%a7'
+    _check_path(object_id='object-01', correct_path='3c0/ff4/240/object-01')
+    _check_path(object_id='object-01', correct_path='ff7/553/449/object-01', algorithm='md5')
+    _check_path(object_id='object-01', correct_path='ff755/34492/object-01', algorithm='md5', tuple_size=5, number_of_tuples=2)
+    _check_path(object_id='object-01', correct_path='object-01', algorithm='md5', tuple_size=0, number_of_tuples=0)
+    _check_path(object_id='object-01', correct_path='ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/object-01', algorithm='md5', tuple_size=2, number_of_tuples=15)
+    _check_path(object_id='..hor/rib:le-$id', correct_path='487/326/d8c/%2e%2ehor%2frib%3ale-%24id')
+    _check_path(object_id='..hor/rib:le-$id', correct_path='083/197/66f/%2e%2ehor%2frib%3ale-%24id', algorithm='md5') #08319766fb6c2935dd175b94267717e0
+    _check_path(object_id='..Hor/rib:lè-$id', correct_path='373/529/21a/%2e%2eHor%2frib%3al%c3%a8-%24id')
+    long_object_id = 'abcdefghij' * 26
+    long_object_id_digest = '55b432806f4e270da0cf23815ed338742179002153cd8d896f23b3e2d8a14359'
+    _check_path(object_id=long_object_id, correct_path=f'55b/432/806/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_digest}')
+    long_object_id_101 = 'abcdefghij' * 10 + 'a'
+    long_object_id_101_digest = '5cc73e648fbcff136510e330871180922ddacf193b68fdeff855683a01464220'
+    _check_path(object_id=long_object_id_101, correct_path=f'5cc/73e/648/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij-{long_object_id_101_digest}')
+
+
+if __name__ == '__main__':
+    run_tests()
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
deleted file mode 100644
index ec279be0..00000000
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
+++ /dev/null
@@ -1 +0,0 @@
-9eedac2a1364d0551b5131f589e5924c5e0ca2af04d8dd4f944d914c6cb5e5dd9a1b2351584716ee2b074122ee4bc1694c8429ef7bfe16bb5cdae054432a45be	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r2/file5 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r2/file5
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r2/file5
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r2/file5
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
similarity index 94%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
index 5e5e5816..fe087d68 100644
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
@@ -7,9 +7,9 @@
   "fixity" : { },
   "manifest" : {
     "4cf0ff5673ec65d9900df95502ed92b2605fc602ca20b6901652c7561b302668026095813af6adb0e663bdcdbe1f276d18bf0de254992a78573ad6574e7ae1f6" : [ "v1/content/file2" ],
-    "891ba5a657177c5f94b5179fe23e31d0c05dd7506bf22d24b280585cdb052aefe5d7336ac7ba697215d6d45a09cbaa7b845d576fee6626fc5fd303b0efe2cc9d" : [ "extensions/0004-mutable-head/head/content/r2/file5" ],
+    "891ba5a657177c5f94b5179fe23e31d0c05dd7506bf22d24b280585cdb052aefe5d7336ac7ba697215d6d45a09cbaa7b845d576fee6626fc5fd303b0efe2cc9d" : [ "extensions/0005-mutable-head/head/content/r2/file5" ],
     "96a26e7629b55187f9ba3edc4acc940495d582093b8a88cb1f0303cf3399fe6b1f5283d76dfd561fc401a0cdf878c5aad9f2d6e7e2d9ceee678757bb5d95c39e" : [ "v1/content/file1" ],
-    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0004-mutable-head/head/content/r1/dir1/file3" ]
+    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0005-mutable-head/head/content/r1/dir1/file3" ]
   },
   "versions" : {
     "v1" : {
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
new file mode 100644
index 00000000..f093cb0e
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
@@ -0,0 +1 @@
+89439a330e797cdb00a88b5aa178df714bc2465b71e4399160f4d633050ebbcdbf724c843231bfa1e67cddc0c82c41ce81b67c6fbc8b23723191a06a3c9b4ed3	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable1/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
deleted file mode 100644
index af515ad8..00000000
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
+++ /dev/null
@@ -1 +0,0 @@
-3d4e2a70bf5aa943134e0b0a92674e3315da26fecb7499438399e35cdd3f61c20544b937ebbbaf3ed3c04c7bd17345ed300dc0a1b08e0e2b3ba6c9979193182e	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/.gitkeep b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/.gitkeep
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/.gitkeep
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/.gitkeep
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r2/file4 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r2/file4
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r2/file4
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r2/file4
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
similarity index 93%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
index 7d2b5e02..ebecb511 100644
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
@@ -6,7 +6,7 @@
   "contentDirectory" : "content",
   "fixity" : { },
   "manifest" : {
-    "3eb3222d4b5629a27dede47a90c7665fcaff1305c2c6c645465edc8278768032ca223f9193f3e9d6bb7a8b950ed284030d256ce1ee33e1de7e9f3e2cb1a834a0" : [ "extensions/0004-mutable-head/head/content/r2/file4" ]
+    "3eb3222d4b5629a27dede47a90c7665fcaff1305c2c6c645465edc8278768032ca223f9193f3e9d6bb7a8b950ed284030d256ce1ee33e1de7e9f3e2cb1a834a0" : [ "extensions/0005-mutable-head/head/content/r2/file4" ]
   },
   "versions" : {
     "v1" : {
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
new file mode 100644
index 00000000..06c3935b
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
@@ -0,0 +1 @@
+8904aa415706c76e7ecc03f26db4b57e6fb02b3edd9ce5d2d9bb543ca23b1ac02e92f3d5c9ddac0117f003fc2cee5a66482e9916fe99f5dfd6adbaefeaaf5789	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable2/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable3/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable3/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable3/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable4/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable4/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable4/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
deleted file mode 100644
index 382f80e9..00000000
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
+++ /dev/null
@@ -1 +0,0 @@
-df4419d36a854205426d174db5b1fcf53ab1df4a55b42f7696bf93ae1c91ef6c76252acb57969ef2d6eb57587ffc10cdaeb8402ad5963b82aca1e79c19246842	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
similarity index 96%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
index e4a99f10..89972b3e 100644
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
@@ -8,7 +8,7 @@
   "manifest" : {
     "4cf0ff5673ec65d9900df95502ed92b2605fc602ca20b6901652c7561b302668026095813af6adb0e663bdcdbe1f276d18bf0de254992a78573ad6574e7ae1f6" : [ "v1/content/file2" ],
     "96a26e7629b55187f9ba3edc4acc940495d582093b8a88cb1f0303cf3399fe6b1f5283d76dfd561fc401a0cdf878c5aad9f2d6e7e2d9ceee678757bb5d95c39e" : [ "v1/content/file1" ],
-    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0004-mutable-head/head/content/r1/dir1/file3" ]
+    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0005-mutable-head/head/content/r1/dir1/file3" ]
   },
   "versions" : {
     "v1" : {
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
new file mode 100644
index 00000000..016c9470
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
@@ -0,0 +1 @@
+467c811380f323f62ed292bd715f05d77973d95062d5c8e95157c1656c7e74fb8852d918526c50003cfceacac58b347063226847d0e7800c3f01d8f46c29938e	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable5/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
deleted file mode 100644
index a4929340..00000000
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json.sha512
+++ /dev/null
@@ -1 +0,0 @@
-70d904d6047a8ab838b4c9716b45b791250174c8a05a7bbab5698fc3188603f7310d4c9fb09a340753d0cd58d9420ea5a12f1dff0bdd388e3c4649b5e54fe51c	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/content/r1/dir1/file3
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/content/r1/dir1/file3
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
similarity index 96%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
index b228e8f3..b3d3398a 100644
--- a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/head/inventory.json
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json
@@ -8,7 +8,7 @@
   "manifest" : {
     "4cf0ff5673ec65d9900df95502ed92b2605fc602ca20b6901652c7561b302668026095813af6adb0e663bdcdbe1f276d18bf0de254992a78573ad6574e7ae1f6" : [ "v1/content/file2" ],
     "96a26e7629b55187f9ba3edc4acc940495d582093b8a88cb1f0303cf3399fe6b1f5283d76dfd561fc401a0cdf878c5aad9f2d6e7e2d9ceee678757bb5d95c39e" : [ "v1/content/file1" ],
-    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0004-mutable-head/head/content/r1/dir1/file3" ]
+    "b10ff867df18165a0e100d99cd3d27f845f7ef9ad84eeb627a53aabaea04805940c3693154b8a32541a31887dda9fb1e667e93307473b1c581021714768bd032" : [ "extensions/0005-mutable-head/head/content/r1/dir1/file3" ]
   },
   "versions" : {
     "v1" : {
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
new file mode 100644
index 00000000..1cf4aff6
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/head/inventory.json.sha512
@@ -0,0 +1 @@
+0ac4800cf955a913680557a68457f55aeebcf5bb74e71bab112ea7d6dae82bdc1f3160f30435107a3d921617ce400ff248635e79ea1edd57f9b967d4725bd4bd	inventory.json
\ No newline at end of file
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r1
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r1
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/revisions/r2
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/revisions/r2
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512 b/ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
similarity index 100%
rename from ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0004-mutable-head/root-inventory.json.sha512
rename to ocfl-java-itest/src/test/resources/expected/repos/mutable6/235/2da/728/2352da7280f1decc3acf1ba84eb945c9fc2b7b541094e1d0992dbffd1b6664cc/extensions/0005-mutable-head/root-inventory.json.sha512
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/replicate1/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/replicate1/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/replicate1/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/replicate2/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/replicate2/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/replicate2/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo-multiple-objects/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo-multiple-objects/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo-multiple-objects/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo1/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo1/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo1/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo10/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo10/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo10/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo11/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo11/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo11/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo12/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo12/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo12/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo13/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo13/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo13/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo14/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo14/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo14/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo15/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo15/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo15/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo16/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo16/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo16/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo17/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo17/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo17/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo2/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo2/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo2/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo3/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo3/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo3/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo4/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo4/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo4/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo5/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo5/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo5/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo7/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo7/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo7/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo8/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo8/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo8/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/repo9/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/repo9/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/repo9/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/rollback1/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/rollback1/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/rollback1/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/rollback2/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/rollback2/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/rollback2/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/rollback3/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/rollback3/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/rollback3/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/windows-safe/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/windows-safe/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/windows-safe/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/expected/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/expected/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/expected/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/invalid-repos/bad-logical-paths/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/invalid-repos/bad-logical-paths/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/invalid-repos/bad-logical-paths/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/invalid-repos/invalid-sidecar-digest/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/invalid-repos/invalid-sidecar-digest/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/invalid-repos/invalid-sidecar-digest/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/invalid-repos/missing-inventory/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/invalid-repos/missing-inventory/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/invalid-repos/missing-inventory/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/invalid-repos/missing-sidecar/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/invalid-repos/missing-sidecar/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/invalid-repos/missing-sidecar/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/invalid-repos/missing-version/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/invalid-repos/missing-version/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/invalid-repos/missing-version/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/different-content/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/different-content/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/different-content/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/different-digest/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/different-digest/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/different-digest/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/invalid-digest-algorithm/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/invalid-digest-algorithm/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/invalid-digest-algorithm/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/invalid-file-fixity/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/invalid-file-fixity/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/invalid-file-fixity/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/invalid-inventory-fixity/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/invalid-inventory-fixity/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/invalid-inventory-fixity/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```
diff --git a/ocfl-java-itest/src/test/resources/sources/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md b/ocfl-java-itest/src/test/resources/sources/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md
new file mode 100644
index 00000000..ed29121c
--- /dev/null
+++ b/ocfl-java-itest/src/test/resources/sources/repos/zero-padded/0004-hashed-n-tuple-storage-layout.md
@@ -0,0 +1,303 @@
+# OCFL Community Extension 0004: Hashed N-tuple Storage Layout
+
+* **Extension Name:** 0004-hashed-n-tuple-storage-layout
+* **Authors:** Peter Winckles
+* **Minimum OCFL Version:** 1.0
+* **OCFL Community Extensions Version:** 1.0
+* **Obsoletes:** n/a
+* **Obsoleted by:** n/a
+
+## Overview
+
+This storage root extension describes how to safely map OCFL object identifiers
+of any length, containing any characters to OCFL object root directories with
+the primary goals of ensuring portability and filesystem performance at the cost
+of directory name transparency.
+
+Using this extension, OCFL object identifiers are hashed and encoded
+as lowercase hex strings. These digests are then divided into _N_
+n-tuple segments, which are used to create nested paths under the OCFL
+storage root.
+
+This approach allows OCFL object identifiers of any composition to be evenly
+distributed across the storage hierarchy. The maximum number of files under any
+given directory is controlled by the number of characters in each n-tuple, and
+the tree depth is controlled by the number of n-tuple segments each digest is
+divided into. Additionally, it obviates the need to handle special characters in
+OCFL object identifiers because the mapped directory names will only ever
+contain the characters `0-9a-f`.
+
+However, this comes at the cost of not being able to identify the OCFL object
+identifier of an object simply by browsing the OCFL storage hierarchy. The ID of
+an object may only be found within its `inventory.json`.
+
+## Parameters
+
+### Summary
+
+* **Name:** `digestAlgorithm`
+    * **Description:** The digest algorithm to apply on the OCFL object
+      identifier; MUST be an algorithm that is allowed in the OCFL fixity block
+    * **Type:** string
+    * **Constraints:** Must not be empty
+    * **Default:** sha256
+* **Name**: `tupleSize`
+    * **Description:** Indicates the segment size (in characters) to split the
+      digest is split into
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `numberOfTuples`
+    * **Description:** Indicates the number of segments to use for path generation
+    * **Type:** number
+    * **Constraints:** An integer between 0 and 32 inclusive
+    * **Default:** 3
+* **Name:** `shortObjectRoot`
+    * **Description:** When true, indicates that the OCFL object root directory
+      name should contain the remainder of the digest not used in the n-tuple
+      segments
+    * **Type:** boolean
+    * **Default:** false
+
+### Details
+
+#### digestAlgorithm
+
+`digestAlgorithm` is defaulted to `sha256`, and it MUST either contain a digest
+algorithm that's [officially supported by the OCFL
+spec](https://ocfl.io/draft/spec/#digest-algorithms) or defined in a community
+extension. The specified algorithm is applied to OCFL object identifiers to
+produce hex encoded digest values that are then mapped to OCFL object root
+paths.
+
+#### tupleSize
+
+`tupleSize` determines the number of digest characters to include in
+each tuple. The tuples are used as directory names. The default value
+is `3`, which means that each intermediate directory in the OCFL
+storage hierarchy could contain up to 4096 sub-directories. Increasing
+this value increases the maximum number of sub-directories per
+directory.
+
+If `tupleSize` is set to `0`, then no tuples are created and `numberOfTuples`
+MUST also equal `0`.
+
+The product of `tupleSize` and `numberOfTuples` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### numberOfTuples
+
+`numberOfTuples` determines how many tuples to create from the digest. The
+tuples are used as directory names, and each successive directory is nested
+within the previous. The default value is `3`, which means that every OCFL
+object root will be 4 directories removed from the OCFL storage root, 3 tuple
+directories plus 1 encapsulation directory. Increasing this value increases the
+depth of the OCFL storage hierarchy.
+
+If `numberOfTuples` is set to `0`, then no tuples are created and `tupleSize`
+MUST also equal `0`.
+
+The product of `numberOfTuples` and `tupleSize` MUST be less than or equal to
+the number of characters in the hex encoded digest.
+
+#### shortObjectRoot
+
+The directory that immediately encapsulates an OCFL object MUST either be named
+using the entire digest or the remainder of the digest that was not used in a
+tuple. When `shortObjectRoot` is set to `false`, the default, the entire digest
+is used, and, when it's `true` only the previously unused remainder is used.
+
+If the product of `tupleSize` and `numberOfTuples` is equal to the number of
+characters in the hex encoded digest, then `shortObjectRoot` MUST be `false`.
+
+## Procedure
+
+The following is an outline of the steps to map an OCFL object identifier to an
+OCFL object root path:
+
+1. The OCFL object identifier, UTF-8 encoded, is hashed using the specified
+   `digestAlgorithm`.
+2. The digest is encoded as a lowercase hex string.
+3. Starting at the beginning of the digest and working forwards, the digest is
+   divided into `numberOfTuples` tuples each containing `tupleSize` characters.
+4. The tuples are joined, in order, using the filesystem path separator.
+5. If `shortObjectRoot` is `true`, the remaining, unused portion of the digest
+   is joined on the end of this path. Otherwise, the entire digest is joined on
+   the end.
+
+## Examples
+
+### Example 1
+
+This example demonstrates what the OCFL storage hierarchy looks like when using
+the default configuration.
+
+#### Parameters
+
+It is not necessary to specify any parameters to use the default configuration.
+However, if you were to do so, it would look like the following:
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 3,
+    "numberOfTuples": 3,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0/ff4/240/3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487/326/d8c/487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0/
+│   └── ff4/
+│       └── 240/
+│           └── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│               ├── 0=ocfl_object_1.0
+│               ├── inventory.json
+│               ├── inventory.json.sha512
+│               └── v1 [...]
+└── 487/
+    └── 326/
+        └── d8c/
+            └── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+                ├── 0=ocfl_object_1.0
+                ├── inventory.json
+                ├── inventory.json.sha512
+                └── v1 [...]
+```
+
+### Example 2
+
+This example demonstrates the effects of modifying the default parameters to use
+a different `digestAlgoirthm`, smaller `tupleSize`, and a larger
+`numberOfTuples`.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "md5",
+    "tupleSize": 2,
+    "numberOfTuples": 15,
+    "shortObjectRoot": true
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | ff75534492485eabb39f86356728884e | `ff/75/53/44/92/48/5e/ab/b3/9f/86/35/67/28/88/4e` |
+| ..hor/rib:le-$id | 08319766fb6c2935dd175b94267717e0 | `08/31/97/66/fb/6c/29/35/dd/17/5b/94/26/77/17/e0` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 08/
+│   └── 31/
+│       └── 97/
+│           └── 66/
+│               └── fb/
+│                   └── 6c/
+│                       └── 29/
+│                           └── 35/
+│                               └── dd/
+│                                   └── 17/
+│                                       └── 5b/
+│                                           └── 94/
+│                                               └── 26/
+│                                                   └── 77/
+│                                                       └── 17/
+│                                                           └── e0/
+│                                                               ├── 0=ocfl_object_1.0
+│                                                               ├── inventory.json
+│                                                               ├── inventory.json.sha512
+│                                                               └── v1 [...]
+└── ff/
+    └── 75/
+        └── 53/
+            └── 44/
+                └── 92/
+                    └── 48/
+                        └── 5e/
+                            └── ab/
+                                └── b3/
+                                    └── 9f/
+                                        └── 86/
+                                            └── 35/
+                                                └── 67/
+                                                    └── 28/
+                                                        └── 88/
+                                                            └── 4e/
+                                                                ├── 0=ocfl_object_1.0
+                                                                ├── inventory.json
+                                                                ├── inventory.json.sha512
+                                                                └── v1 [...]
+```
+
+### Example 3
+
+This example demonstrates what happens when `tupleSize` and `numberOfTuples` are
+set to `0`. This is an edge case and not a recommended configuration.
+
+#### Parameters
+
+```json
+{
+    "extensionName": "0004-hashed-n-tuple-storage-layout",
+    "digestAlgorithm": "sha256",
+    "tupleSize": 0,
+    "numberOfTuples": 0,
+    "shortObjectRoot": false
+}
+```
+
+#### Mappings
+
+| Object ID | Digest | Object Root Path |
+| --------- | ------ | ---------------- |
+| object-01 | 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4 | `3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4` |
+| ..hor/rib:le-$id | 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d | `487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d` |
+
+#### Storage Hierarchy
+
+```
+[storage_root]/
+├── 0=ocfl_1.0
+├── ocfl_layout.json
+├── extensions/
+│   └── 0004-hashed-n-tuple-storage-layout/
+│       └── config.json
+├── 3c0ff4240c1e116dba14c7627f2319b58aa3d77606d0d90dfc6161608ac987d4/
+│   ├── 0=ocfl_object_1.0
+│   ├── inventory.json
+│   ├── inventory.json.sha512
+│   └── v1 [...]
+└── 487326d8c2a3c0b885e23da1469b4d6671fd4e76978924b4443e9e3c316cda6d/
+    ├── 0=ocfl_object_1.0
+    ├── inventory.json
+    ├── inventory.json.sha512
+    └── v1 [...]
+```