title: "Certificate Management Messages over CMS (CMC): Compliance Requirements" abbrev: "CMC: Compliance" category: std obsoletes: 5274, 6402
docname: draft-ietf-lamps-rfc5274bis-latest submissiontype: IETF ipr: pre5378Trust200902 number: date: consensus: true v: 3 area: SEC workgroup: LAMPS Working Group keyword:
- Public Key Infrastructure
- Cryptographic Message Syntax
- Certificate Management
- Compliance venue: group: WG type: LAMPS mail: [email protected] arch: https://mailarchive.ietf.org/arch/browse/spasm/ github: TBD
ins: J. Mandel, Ed.
name: Joseph Mandel
org: AKAYLA, Inc.
email: [email protected]
- ins: S. Turner, Ed. name: Sean Turner organization: sn3rd email: [email protected]
name: Michael Myers org: TraceRoute Security, Inc.
normative: CMC-STRUCT: I-D.ietf-lamps-rfc5272bis CMC-TRANS: I-D.ietf-lamps-rfc5273bis CMS: RFC5652 CMS-AES: RFC3565 CMS-ALG: RFC3370 CMS-DH: RFC2631 CRMF: RFC4211 CMS-RSA-OAEP: RFC3560 CMS-RSA-PSS: RFC4056 DH-POP: RFC6955 RSA-256: RFC4055 PBKDF2: RFC2898 AES-WRAP: RFC3394
informative: PKCS10: RFC2986 SMALL-SUB-GROUP: RFC2785 HASH-ATTACKS: RFC4270 CMC-COMPv1: I-D.ietf-lamps-rfc5274bis CMC-Updates: RFC6402
--- abstract
This document provides a set of compliance statements about the CMC (Certificate Management over CMS) enrollment protocol. The ASN.1 structures and the transport mechanisms for the CMC enrollment protocol are covered in other documents. This document provides the information needed to make a compliant version of CMC.
This document obsoletes RFCs 5274 and 6402.
--- middle
The CMC (Certificate Management over CMS) protocol is designed in terms of a client/server relationship. In the simplest case, the client is the requestor of the certificate (i.e., the End Entity (EE)) and the server is the issuer of the certificate (i.e., the Certification Authority (CA)). The introduction of a Registration Authority (RA) into the set of agents complicates the picture only slightly. The RA becomes the server with respect to the certificate requestor, and it becomes the client with respect to the certificate issuer. Any number of RAs can be inserted into the picture in this manner.
The RAs may serve specialized purposes that are not currently covered by this document. One such purpose would be a Key Escrow agent. As such, all certificate requests for encryption keys would be directed through this RA and it would take appropriate action to do the key archival. Key recovery requests could be defined in the CMC methodology allowing for the Key Escrow agent to perform that operation acting as the final server in the chain of agents.
If there are multiple RAs in the system, it is considered normal that not all RAs will see all certificate requests. The routing between the RAs may be dependent on the content of the certificate requests involved.
This document is divided into six sections, each section specifying the requirements that are specific to a class of agents in the CMC model. These are 1) all Entities, 2) all Servers, 3) all Clients, 4) all End-Entities, 5) all Registration Authorities, 6) all Certification Authorities.
This document obsoletes {{CMC-COMPv1}} and {{CMC-Updates}}.
There are several different terms, abbreviations, and acronyms used in this document that we define here for convenience and consistency of usage:
End-Entity (EE): : Refers to the entity that owns a key pair and for whom a certificate is issued.
Registration Authority (RA) or Local RA (LRA):
: Refers to an entity that acts as an intermediary between the EE and the CA. Multiple RAs can exist between the End-Entity and the Certification Authority. RAs may perform additional services such as key generation or key archival. This document uses the term RA for both RA and LRA.
Certification Authority (CA):
: Refers to the entity that issues certificates.
Client:
: Refers to an entity that creates a PKI Request. In this document, both RAs and EEs can be clients.
Server:
: Refers to the entities that process PKI Requests and create PKI Responses. In this document both CAs and RAs can be servers.
PKCS #10:
: Refers to the Public Key Cryptography Standard #10 {{PKCS10}}, which defines a certification request syntax.
CRMF:
: Refers to the Certificate Request Message Format RFC {{CRMF}}. CMC uses this certification request syntax defined in this document as part of the protocol.
CMS:
: Refers to the Cryptographic Message Syntax RFC {{CMS}}. This document provides for basic cryptographic services including encryption and signing with and without key management.
PKI Request/Response:
: Refers to the requests/responses described in this document. PKI Requests include certification requests, revocation requests, etc. PKI Responses include certs-only messages, failure messages, etc.
Proof-of-Identity:
: Refers to the client proving they are who they say that they are to the server.
Proof-of-Possession (POP):
: Refers to a value that can be used to prove that the private key corresponding to a public key is in the possession and can be used by an end-entity.
Transport wrapper:
: Refers to the outermost CMS wrapping layer.
{::boilerplate bcp14-tagged}
Note: For now, this section will be list of the changes introduced by each version. After WGLC, this section will be finalized.TODO for -03 WG version:
- Add cryptographic algorithm requirements
-02 WG version changes:
- Reformat cryptographic algorithm section
-01 WG version changes:
- Updated references
-00 WG version changes:
- Added pre-5378 boilerplate
-02 individual version changes:
- Updated text in intro
- Changed "all agents" to "all entities" in overview
- Updated section header numbering
-01 individual version changes:
- Changed RFC 5272 references to draft-mandel-lamps-rfc5272bis
- Changed RFC 5273 references to draft-mandel-lamps-rfc5273bis
-00 individual version changes:
- Added "Changes Since 5274 and 6402" section
- Updated references
- Merged {{CMC-Updates}} text
- Updated and moved Acknowledgments
All {{CMC-STRUCT}} and {{CMC-TRANS}} compliance statements MUST be adhered to unless specifically stated otherwise in this document.
All entities MUST support Full PKI Requests, Simple PKI Responses, and Full PKI Responses. Servers SHOULD support Simple PKI Requests.
All entities MUST support the use of the CRMF syntax for certification requests. Support for the PKCS #10 syntax for certification requests SHOULD be implemented by servers.
The extendedFailInfo field SHOULD NOT be populated in the CMCStatusInfoV2 object; the failInfo field SHOULD be used to relay this information. If the extendedFailInfo field is used, it is suggested that an additional CMCStatusInfoV2 item exist for the same body part with a failInfo field.
All entities MUST implement the HTTP transport mechanism as defined in {{CMC-TRANS}}. Other transport mechanisms MAY be implemented.
The following table shows the algorithm requirements that must be used for SignedData and AuthenticatedData.
Description of the columns in the table:
Use: Description of the key usage Mandatory: Algorithms that MUST be supported by conforming implementations Recommend: Algorithms that SHOULD be supported Optional: Algorithms that MAY be supported
| Use | Mandatory | Recommend | Optional | |:-----------------------|:-----------|:-------------| | Verify signature in SignedData | TBD | TBD | other algorithms | | Generate signature for SignedData | TBD | TBD | other algorithms | | Content encryption for EnvelopedData | TBD | TBD | other algorithms | | Key transport for EnvelopedData | TBD | TBD | other algorithms | |:-----------------------|:-----------|:-------------|:-------------| {: #AlgReq-SD-and-AD title="Algorithm Requirements for SignedData and AuthenticatedData"}
The following table shows the algorithm requirements for EnvelopedData and AuthenticatedData if supported by the entity.
Description of the columns in the table:
Use: Description of key usage Mandatory: Algorithms that MUST be supported by conforming implementations Recommend: Algorithms that SHOULD be supported Optional: Algorithms that MAY be supported
| Use | Mandatory | Recommend | Optional | |:-----------------------|:-----------|:-------------| | key agreement for EnvelopedData | TBD | TBD | TBD | | PasswordRecipientInfo for EnvelopedData or AuthenticatedData | TBD | TBD | TBD | | AuthenticatedData | PasswordRecipientInfo | TBD | TBD | |:-----------------------|:-----------|:-------------|:-------------| {: #AlgReq-ED-and-AD title="Algorithm Requirements for EnvelopedData and AuthenticatedData"}
The following table shows the algorithm requirements for Controls.
Description of the columns in the table:
Control: Control carried as part of Full PKI Requests and Responses AlgId: Notes the algorithm identifier which is used Mandatory: Algorithms that MUST be supported by conforming implementations Recommend: Algorithms that SHOULD be supported Optional: Algorithms that MAY be supported
| Control | AlgId | Mandatory | Recommend | Optional |
|---|---|---|---|---|
| Identity Proof Version 2 control | hashAlgId | TBD | TBD | TBD |
| Identity Proof Version 2 control | macAlgId | TBD | TBD | TBD |
| Pop Link Witness Version 2 control | keyGenAlgorithm | TBD | TBD | TBD |
| Pop Link Witness Version 2 control | macAlgorithm | TBD | TBD | TBD |
| Encrypted POP and Decrypted POP controls | witnessAlgID | TBD | TBD | TBD |
| Encrypted POP and Decrypted POP controls | thePOPAlgID | TBD | TBD | TBD |
| Publish Trust Anchors control | hashAlgorithm | TBD | TBD | TBD |
| :----------------------- | :----------- | :------------- | :------------- | :------------- |
| {: #AlgReq-Controls title="Algorithm Requirements for Controls"} |
The following table shows the algorithm requirements for Proof of Possession (POP) of DH Certification Requests and the No-Signature mechanism.
Description of the columns in the table:
Use: Request type from Appendix C of {{CMC-STRUCT}} Mandatory: Algorithms that MUST be supported by conforming implementations Recommend: Algorithms that SHOULD be supported Optional: Algorithms that MAY be supported
| Use | Mandatory | Recommend | Optional |
|---|---|---|---|
| EE generates DH keys for certification | EE and CA/RA {{Section 4 of DH-POP}} | {TBD} | EE and CA/RA {{Section 3 of DH-POP}} |
| No-Signature Signature Mechanism | Appendix C of {{CMC-STRUCT}} | {TBD} | {TBD} |
| :----------------------- | :----------- | :------------- | :------------- |
| {: #AlgReq-DH-and-NS title="Algorithm Requirements for DH Certification Requests and the No-Signature mechanism"} |
The following table lists the name and level of support required for each control.
| Control | EE | RA | CA |
|---|---|---|---|
| Extended CMC Status Info | MUST | MUST | MUST |
| CMC Status Info | SHOULD | SHOULD | SHOULD |
| Identity Proof Version 2 | MUST | MUST | MUST |
| Identity Proof | SHOULD | SHOULD | SHOULD |
| Identification | MUST | MUST | MUST |
| POP Link Random | MUST | MUST | MUST |
| POP Link Witness Version 2 | MUST | MUST | MUST |
| POP Link Witness | SHOULD | MUST | MUST |
| Data Return | MUST | MUST | MUST |
| Modify Cert Request | N/A | MUST | (2) |
| Add Extensions | N/A | MAY | (1) |
| Transaction ID | MUST | MUST | MUST |
| Sender Nonce | MUST | MUST | MUST |
| Recipient Nonce | MUST | MUST | MUST |
| Encrypted POP | (4) | (5) | SHOULD |
| Decrypted POP | (4) | (5) | SHOULD |
| RA POP Witness | N/A | SHOULD | (1) |
| Get Certificate | optional | optional | optional |
| Get CRL | optional | optional | optional |
| Revocation Request | SHOULD | SHOULD | MUST |
| Registration Info | SHOULD | SHOULD | SHOULD |
| Response Information | SHOULD | SHOULD | SHOULD |
| Query Pending | MUST | MUST | MUST |
| Confirm Cert. Acceptance | MUST | MUST | MUST |
| Publish Trust Anchors | (3) | (3) | (3) |
| Authenticate Data | (3) | (3) | (3) |
| Batch Request | N/A | MUST | (2) |
| Batch Responses | N/A | MUST | (2) |
| Publication Information | optional | optional | optional |
| Control Processed | N/A | MUST | (2) |
| RA Identity Proof Witness | N/A | MUST | (2) |
| Response Body | (6) | (6) | N/A. |
| {: #cmc-controls title="CMC Control Attributes"} |
Notes:
-
CAs SHOULD implement this control if designed to work with RAs.
-
CAs MUST implement this control if designed to work with RAs.
-
Implementation is optional for these controls. We strongly suggest that they be implemented in order to populate client trust anchors.
-
EEs only need to implement this if (a) they support key agreement algorithms or (b) they need to operate in environments where the hardware keys cannot provide POP.
-
RAs SHOULD implement this if they implement RA POP Witness.
-
EE's SHOULD implement if designed to work with RAs and MUST implement if intended to be used in environments where RAs are used for identity validation or key generation. RAs SHOULD implement and validate responses for consistency.
Strong consideration should be given to implementing the Authenticate Data and Publish Trust Anchors controls as this gives a simple method for distributing trust anchors into clients without user intervention.
The following additional restrictions are placed on CRMF features:
The registration control tokens id-regCtrl-regToken and id-regCtrl- authToken MUST NOT be used. No specific CMC feature is used to replace these items, but generally the CMC controls identification and identityProof will perform the same service and are more specifically defined.
The control token id-regCtrl-pkiArchiveOptions SHOULD NOT be supported. An alternative method is under development to provide this functionality.
The behavior of id-regCtrl-oldCertID is not presently used. It is replaced by issuing the new certificate and using the id-cmc- publishCert to remove the old certificate from publication. This operation would not normally be accompanied by an immediate revocation of the old certificate; however, that can be accomplished by the id-cmc-revokeRequest control.
The id-regCtrl-protocolEncrKey is not used.
There are no additional requirements.
There are no additional requirements.
If an entity implements Diffie-Hellman, it MUST implement either the DH-POP Proof-of-Possession as defined in {{Section 4 of DH-POP}} or the challenge-response POP controls id-cmc-encryptedPOP and id-cmc- decryptedPOP.
RAs SHOULD be able to do delegated POP. RAs implementing this feature MUST implement the id-cmc-lraPOPWitness control.
All RAs MUST implement the promotion of the id-aa-cmc-unsignedData as covered in {{Section 3.2.3 of CMC-STRUCT}}.
Providing for CAs to work in an environment with RAs is strongly suggested. Implementation of such support is strongly suggested as this permits the delegation of substantial administrative interaction onto an RA rather than at the CA.
CAs MUST perform at least minimal checks on all public keys before issuing a certificate. At a minimum, a check for syntax would occur with the POP operation. Additionally, CAs SHOULD perform simple checks for known bad keys such as small subgroups for DSA-SHA1 and DH keys {{SMALL-SUB-GROUP}} or known bad exponents for RSA keys.
CAs MUST enforce POP checking before issuing any certificate. CAs MAY delegate the POP operation to an RA for those cases where 1) a challenge/response message pair must be used, 2) an RA performs escrow of a key and checks for POP in that manner, or 3) an unusual algorithm is used and that validation is done at the RA.
CAs SHOULD implement both the DH-POP Proof-of-Possession as defined in {{Section 4 of DH-POP}} and the challenge-response POP controls id- cmc-encryptedPOP and id-cmc-decryptedPOP.
This document uses {{CMC-STRUCT}} and {{CMC-TRANS}} as building blocks to this document. The security sections of those two documents are included by reference.
Knowledge of how an entity is expected to operate is vital in determining which sections of requirements are applicable to that entity. Care needs to be taken in determining which sections apply and fully implementing the necessary code.
Cryptographic algorithms have and will be broken or weakened. Implementers and users need to check that the cryptographic algorithms listed in this document make sense from a security level. The IETF from time to time may issue documents dealing with the current state of the art. Two examples of such documents are {{SMALL-SUB-GROUP}} and {{HASH-ATTACKS}}.
--- back
{:numbered="false"}
Obviously, the authors of this version of the document would like to thank Jim Schaad and Michael Myers for their work on the previous version of this document.
The acknowledgment from the previous version of this document follows:
The authors and the PKIX Working Group are grateful for the participation of Xiaoyi Liu and Jeff Weinstein in helping to author the original versions of this document.
The authors would like to thank Brian LaMacchia for his work in developing and writing up many of the concepts presented in this document. The authors would also like to thank Alex Deacon and Barb Fox for their contributions.