Add ANSI-X9.63-KDF

Cargo.toml

@@ -2,7 +2,7 @@
 resolver = "2"
 members = [
     "hkdf",
-    "concat-kdf",
+    "concat-kdf", "ansi-x963-kdf",
 ]
 
 [profile.dev]

README.md

@@ -10,6 +10,7 @@ Collection of [Key Derivation Functions][KDF] (KDF) written in pure Rust.
 |--------------|----------------|:---------------------------------------------------------------------------------------------------:|:------------------------------------------------------------------------------------:|:-----------------------:|
 | [HKDF]       | [`hkdf`]       |       [![crates.io](https://img.shields.io/crates/v/hkdf.svg)](https://crates.io/crates/hkdf)       |       [![Documentation](https://docs.rs/hkdf/badge.svg)](https://docs.rs/hkdf)       | ![MSRV 1.41][msrv-1.72] |
 | [Concat-KDF] | [`concat-kdf`] | [![crates.io](https://img.shields.io/crates/v/concat-kdf.svg)](https://crates.io/crates/concat-kdf) | [![Documentation](https://docs.rs/concat-kdf/badge.svg)](https://docs.rs/concat-kdf) | ![MSRV 1.56][msrv-1.72] |
+| [ANSI-X9.63-KDF] | [`ansi-x963-kdf`] | [![crates.io](https://img.shields.io/crates/v/ansi-x963-kdf.svg)](https://crates.io/crates/ansi-x963-kdf) | [![Documentation](https://docs.rs/ansi-x963-kdf/badge.svg)](https://docs.rs/ansi-x963-kdf) | ![MSRV 1.56][msrv-1.72] |
 
 *NOTE: for password-based KDFs (e.g. Argon2, PBKDF2, scrypt), please see [RustCrypto/password-hashes]*
 
@@ -43,10 +44,12 @@ Unless you explicitly state otherwise, any contribution intentionally submitted
 
 [`hkdf`]: ./hkdf
 [`concat-kdf`]: ./concat-kdf
+[`ansi-x963-kdf`]: ./ansi-x963-kdf
 
 [//]: # (algorithms)
 
 [KDF]: https://en.wikipedia.org/wiki/Key_derivation_function
 [HKDF]: https://en.wikipedia.org/wiki/HKDF
 [Concat-KDF]: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-56ar.pdf
+[ANSI-X9.63-KDF]: https://www.secg.org/sec1-v2.pdf
 [RustCrypto/password-hashes]: https://github.com/RustCrypto/password-hashes

ansi-x963-kdf/CHANGELOG.md

@@ -0,0 +1,8 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## 0.1.0 (2024-04-10)
+- Initial release

ansi-x963-kdf/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "ansi-x963-kdf"
+version = "0.1.0"
+description = "ANSI X9.63 Key Derivation Function (ANSI-X9.63-KDF)"
+authors = ["RustCrypto Developers"]
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+edition = "2021"
+documentation = "https://docs.rs/ansi-x963-kdf"
+repository = "https://github.com/RustCrypto/KDFs"
+keywords = ["crypto", "ansi-x963-kdf", "KDF", "SEC1"]
+categories = ["cryptography", "no-std"]
+rust-version = "1.72"
+
+[dependencies]
+digest = "=0.11.0-pre.9"
+
+[dev-dependencies]
+hex-literal = "0.4"
+sha2 = { version = "=0.11.0-pre.4", default-features = false }
+
+[features]
+std = []
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+

ansi-x963-kdf/README.md

@@ -0,0 +1,59 @@
+# RustCrypto: ANSI X9.63 Key Derivation Function (ANSI-X9.63-KDF)
+
+[![crate][crate-image]][crate-link]
+[![Docs][docs-image]][docs-link]
+![Apache2/MIT licensed][license-image]
+![Rust Version][rustc-image]
+[![Project Chat][chat-image]][chat-link]
+[![Build Status][build-image]][build-link]
+
+Pure Rust implementation of the ANSI X9.63 Key Derivation Function (ANSI-X9.63-KDF) generic over hash function. 
+This function is described in the section 3.6.1 of [SEC 1: Elliptic Curve Cryptography](http://www.secg.org/sec1-v2.pdf).
+
+# Usage
+
+The most common way to use ANSI-X9.63-KDF is as follows: you generate a shared secret with other party (e.g. via Diffie-Hellman algorithm) 
+and use key derivation function to derive a shared key.
+
+```rust
+let mut key = [0u8; 32];
+ansi_x963_kdf::derive_key_into::<sha2::Sha256>(b"shared-secret", b"other-info", &mut key).unwrap();
+```
+
+## Minimum Supported Rust Version
+
+Rust **1.72** or higher.
+
+Minimum supported Rust version can be changed in the future, but it will be
+done with a minor version bump.
+
+## SemVer Policy
+
+- All on-by-default features of this library are covered by SemVer
+- MSRV is considered exempt from SemVer as noted above
+
+## License
+
+Licensed under either of:
+
+* [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
+* [MIT license](http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
+
+[crate-image]: https://img.shields.io/crates/v/ansi-x963-kdf.svg
+[crate-link]: https://crates.io/crates/ansi-x963-kdf
+[docs-image]: https://docs.rs/ansi-x963-kdf/badge.svg
+[docs-link]: https://docs.rs/ansi-x963-kdf/
+[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.72+-blue.svg
+[chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
+[chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/260043-KDFs
+[build-image]: https://github.com/RustCrypto/KDFs/workflows/ansi-x963-kdf/badge.svg?branch=master&event=push
+[build-link]: https://github.com/RustCrypto/KDFs/actions?query=workflow:ansi-x963-kdf

ansi-x963-kdf/src/lib.rs

@@ -0,0 +1,121 @@
+//! An implementation of ANSI-X9.63 KDF Key Derivation Function.
+//!
+//! This function is described in the section 3.6.1 of [SEC 1: Elliptic Curve Cryptography][1].
+//!
+//! # Usage
+//!
+//! The most common way to use ANSI-X9.63 KDF is as follows: you generate a shared secret
+//! with other party (e.g. via Diffie-Hellman algorithm) and use key derivation function
+//! to derive a shared key.
+//!
+//! ```rust
+//! let mut key = [0u8; 32];
+//! ansi_x963_kdf::derive_key_into::<sha2::Sha256>(b"shared-secret", b"other-info", &mut key).unwrap();
+//! ```
+//!
+//! [1]: https://www.secg.org/sec1-v2.pdf
+
+#![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
+
+use core::fmt;
+use digest::{array::typenum::Unsigned, Digest, FixedOutputReset, Update};
+
+#[cfg(feature = "std")]
+extern crate std;
+
+/// ANSI-X9.63 KDF errors.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Error {
+    /// The length of the secret is zero.
+    NoSecret,
+    /// The length of the output is zero.
+    NoOutput,
+    /// The length of the input is too big
+    InputOverflow,
+    /// The length of the output is too big.
+    CounterOverflow,
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        f.write_str(match self {
+            Error::NoSecret => "Buffer for secret has zero length.",
+            Error::NoOutput => "Buffer for key has zero length.",
+            Error::InputOverflow => "Input length is to big.",
+            Error::CounterOverflow => "Requested key length is to big.",
+        })
+    }
+}
+
+#[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+impl ::std::error::Error for Error {}
+
+/// Derives `key` in-place from `secret` and `shared_info`.
+/// ```rust
+/// let mut key = [0u8; 42];
+/// ansi_x963_kdf::derive_key_into::<sha2::Sha256>(b"top-secret", b"info", &mut key).unwrap();
+/// ```
+pub fn derive_key_into<D>(secret: &[u8], shared_info: &[u8], key: &mut [u8]) -> Result<(), Error>
+where
+    D: Digest + FixedOutputReset,
+{
+    if secret.is_empty() {
+        return Err(Error::NoSecret);
+    }
+
+    if key.is_empty() {
+        return Err(Error::NoOutput);
+    }
+
+    // 1. Check if |Z| + |SharedInfo| + 4 >= hashmaxlen
+    if secret.len() + shared_info.len() + 4 >= D::OutputSize::USIZE * (u32::MAX as usize) {
+        return Err(Error::InputOverflow);
+    }
+
+    // Counter overflow is possible only on architectures with usize bigger than 4 bytes.
+    const OVERFLOW_IS_POSSIBLE: bool = core::mem::size_of::<usize>() > 4;
+
+    // 2. Check that keydatalen < hashlen × (2^32 − 1)
+    if OVERFLOW_IS_POSSIBLE && (key.len() >= D::OutputSize::USIZE * (u32::MAX as usize)) {
+        return Err(Error::CounterOverflow);
+    }
+
+    let mut digest = D::new();
+
+    // 3. Initiate a 4 octet, big-endian octet string Counter as 00000001
+    let mut counter: u32 = 1;
+
+    // 4. For i = 1 to keydatalen/hashlen,
+    for chunk in key.chunks_mut(D::OutputSize::USIZE) {
+        // 4.1 Compute Ki = Hash(Z ‖ Counter ‖ [SharedInfo]) using the selected hash function
+        Update::update(&mut digest, secret);
+        Update::update(&mut digest, &counter.to_be_bytes());
+        Update::update(&mut digest, shared_info);
+        chunk.copy_from_slice(&digest.finalize_reset()[..chunk.len()]);
+        // 4.2. Increment Counter
+        counter += 1;
+    }
+
+    Ok(())
+}
+
+/// Derives and returns `length` bytes key from `secret` and `shared_info`.
+/// ```rust
+/// let key = ansi_x963_kdf::derive_key::<sha2::Sha256>(b"top-secret", b"info", 42).unwrap();
+/// ```
+#[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+pub fn derive_key<D>(
+    secret: &[u8],
+    shared_info: &[u8],
+    length: usize,
+) -> Result<std::vec::Vec<u8>, Error>
+where
+    D: Digest + FixedOutputReset,
+{
+    let mut key = std::vec![0u8; length];
+    derive_key_into::<D>(secret, shared_info, &mut key)?;
+    Ok(key)
+}