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rfc:rfc8756



Independent Submission M. Jenkins Request for Comments: 8756 L. Zieglar Category: Informational NSA ISSN: 2070-1721 March 2020

   Commercial National Security Algorithm (CNSA) Suite Profile of
                  Certificate Management over CMS

Abstract

 This document specifies a profile of the Certificate Management over
 CMS (CMC) protocol for managing X.509 public key certificates in
 applications that use the Commercial National Security Algorithm
 (CNSA) Suite published by the United States Government.
 The profile applies to the capabilities, configuration, and operation
 of all components of US National Security Systems that manage X.509
 public key certificates over CMS.  It is also appropriate for all
 other US Government systems that process high-value information.
 The profile is made publicly available here for use by developers and
 operators of these and any other system deployments.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for informational purposes.
 This is a contribution to the RFC Series, independently of any other
 RFC stream.  The RFC Editor has chosen to publish this document at
 its discretion and makes no statement about its value for
 implementation or deployment.  Documents approved for publication by
 the RFC Editor are not candidates for any level of Internet Standard;
 see Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8756.

Copyright Notice

 Copyright (c) 2020 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.

Table of Contents

 1.  Introduction
   1.1.  Terminology
 2.  The Commercial National Security Algorithm Suite
 3.  Requirements and Assumptions
 4.  Client Requirements: Generating PKI Requests
   4.1.  Tagged Certification Request
   4.2.  Certificate Request Message
 5.  RA Requirements
   5.1.  RA Processing of Requests
   5.2.  RA-Generated PKI Requests
   5.3.  RA-Generated PKI Responses
 6.  CA Requirements
   6.1.  CA Processing of PKI Requests
   6.2.  CA-Generated PKI Responses
 7.  Client Requirements: Processing PKI Responses
 8.  Shared-Secrets
 9.  Security Considerations
 10. IANA Considerations
 11. References
   11.1.  Normative References
   11.2.  Informative References
 Appendix A.  Scenarios
   A.1.  Initial Enrollment
   A.2.  Rekey
 Authors' Addresses

1. Introduction

 This document specifies a profile of the Certificate Management over
 CMS (CMC) protocol to comply with the United States National Security
 Agency's Commercial National Security Algorithm (CNSA) Suite [CNSA].
 The profile applies to the capabilities, configuration, and operation
 of all components of US National Security Systems [SP80059].  It is
 also appropriate for all other US Government systems that process
 high-value information.  It is made publicly available for use by
 developers and operators of these and any other system deployments.
 This document does not define any new cryptographic algorithm suites;
 instead, it defines a CNSA-compliant profile of CMC.  CMC is defined
 in [RFC5272], [RFC5273], and [RFC5274] and is updated by [RFC6402].
 This document profiles CMC to manage X.509 public key certificates in
 compliance with the CNSA Suite Certificate and Certificate Revocation
 List (CRL) profile [RFC8603].  This document specifically focuses on
 defining CMC interactions for both the initial enrollment and rekey
 of CNSA Suite public key certificates between a client and a
 Certification Authority (CA).  One or more Registration Authorities
 (RAs) may act as intermediaries between the client and the CA.  This
 profile may be further tailored by specific communities to meet their
 needs.  Specific communities will also define certificate policies
 that implementations need to comply with.

1.1. Terminology

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.
 The terminology in [RFC5272], Section 2.1 applies to this profile.
 The term "certificate request" is used to refer to a single PKCS #10
 or Certificate Request Message Format (CRMF) structure.  All PKI
 Requests are Full PKI Requests, and all PKI Responses are Full PKI
 Responses; the respective set of terms should be interpreted
 synonymously in this document.

2. The Commercial National Security Algorithm Suite

 The National Security Agency (NSA) profiles commercial cryptographic
 algorithms and protocols as part of its mission to support secure,
 interoperable communications for US Government National Security
 Systems.  To this end, it publishes guidance both to assist with the
 US Government transition to new algorithms and to provide vendors --
 and the Internet community in general -- with information concerning
 their proper use and configuration within the scope of US Government
 National Security Systems.
 Recently, cryptographic transition plans have become overshadowed by
 the prospect of the development of a cryptographically relevant
 quantum computer.  The NSA has established the Commercial National
 Security Algorithm (CNSA) Suite to provide vendors and IT users near-
 term flexibility in meeting their cybersecurity interoperability
 requirements.  The purpose behind this flexibility is to avoid having
 vendors and customers make two major transitions in a relatively
 short timeframe, as we anticipate a need to shift to quantum-
 resistant cryptography in the near future.
 The NSA is authoring a set of RFCs, including this one, to provide
 updated guidance concerning the use of certain commonly available
 commercial algorithms in IETF protocols.  These RFCs can be used in
 conjunction with other RFCs and cryptographic guidance (e.g., NIST
 Special Publications) to properly protect Internet traffic and data-
 at-rest for US Government National Security Systems.

3. Requirements and Assumptions

 Elliptic Curve Digital Signature Algorithm (ECDSA) and Elliptic Curve
 Diffie-Hellman (ECDH) key pairs are on the P-384 curve.  FIPS 186-4
 [FIPS186], Appendix B.4 provides useful guidance for elliptic curve
 key pair generation that SHOULD be followed by systems that conform
 to this document.
 RSA key pairs (public, private) are identified by the modulus size
 expressed in bits; RSA-3072 and RSA-4096 are computed using moduli of
 3072 bits and 4096 bits, respectively.
 RSA signature key pairs used in CNSA Suite-compliant implementations
 are either RSA-3072 or RSA-4096.  The RSA exponent e MUST satisfy
 2^(16) < e < 2^(256) and be odd per [FIPS186].
 It is recognized that, while the vast majority of RSA signatures are
 currently made using the RSASSA-PKCS1-v1_5 algorithm, the preferred
 RSA signature scheme for new applications is RSASSA-PSS.  CNSA Suite-
 compliant X.509 certificates will be issued in accordance with
 [RFC8603], and while those certificates must be signed and validated
 using RSASSA-PKCS1-v1_5, the subject's private key can be used to
 generate signatures of either signing scheme.  Where use of RSASSA-
 PSS is indicated in this document, the following parameters apply:
  • The hash algorithm MUST be id-sha384 as defined in [RFC8017];
  • The mask generation function MUST use the algorithm identifier

mfg1SHA384Identifier as defined in [RFC4055];

  • The salt length MUST be 48 octets; and
  • The trailerField MUST have value 1.
 These parameters will not appear in a certificate and MUST be
 securely communicated with the signature, as required by Section 2.2
 of [RFC4056].  Application developers are obliged to ensure that the
 chosen signature scheme is appropriate for the application and will
 be interoperable within the intended operating scope of the
 application.
 This document assumes that the required trust anchors have been
 securely provisioned to the client and, when applicable, to any RAs.
 All requirements in [RFC5272], [RFC5273], [RFC5274], and [RFC6402]
 apply, except where overridden by this profile.
 This profile was developed with the scenarios described in Appendix A
 in mind.  However, use of this profile is not limited to just those
 scenarios.
 The term "client" in this profile typically refers to an end-entity.
 However, it may instead refer to a third party acting on the end-
 entity's behalf.  The client may or may not be the entity that
 actually generates the key pair, but it does perform the CMC protocol
 interactions with the RA and/or CA.  For example, the client may be a
 token management system that communicates with a cryptographic token
 through an out-of-band secure protocol.
 This profile uses the term "rekey" in the same manner as CMC does
 (defined in Section 2 of [RFC5272]).  The profile makes no specific
 statements about the ability to do "renewal" operations; however, the
 statements applicable to "rekey" should be applied to "renewal" as
 well.
 This profile may be used to manage RA and/or CA certificates.  In
 that case, the RA and/or CA whose certificate is being managed is
 considered to be the end-entity.
 This profile does not discuss key establishment certification
 requests from cryptographic modules that cannot generate a one-time
 signature with a key establishment key for proof-of-possession
 purposes.  In that case, a separate profile would be needed to define
 the use of another proof-of-possession technique.

4. Client Requirements: Generating PKI Requests

 This section specifies the conventions employed when a client
 requests a certificate from a Public Key Infrastructure (PKI).
 The Full PKI Request MUST be used; it MUST be encapsulated in a
 SignedData; and the SignedData MUST be constructed in accordance with
 [RFC8755].  The PKIData content type defined in [RFC5272] is used
 with the following additional requirements:
  • controlSequence SHOULD be present.
  1. TransactionId and SenderNonce SHOULD be included. Other CMC

controls MAY be included.

  1. If the request is being authenticated using a shared-secret,

then Identity Proof Version 2 control MUST be included with the

       following constraints:
       o  hashAlgId MUST be id-sha384 for all certification requests
          (algorithm OIDs are defined in [RFC5754]).
       o  macAlgId MUST be HMAC-SHA384 (the Hashed Message
          Authentication Code (HMAC) algorithm is defined in
          [RFC4231]).
  1. If the subject name included in the certification request is

NULL or otherwise does not uniquely identify the end-entity,

       then the POP Link Random control MUST be included, and the POP
       Link Witness Version 2 control MUST be included in the inner
       PKCS #10 [RFC2986] or Certificate Request Message Format (CRMF)
       [RFC4211] request as described in Sections 4.1 and 4.2.
  • reqSequence MUST be present. It MUST include at least one tcr

(see Section 4.1) or crm (see Section 4.2) TaggedRequest. Support

    for the orm choice is OPTIONAL.
 The private signing key used to generate the encapsulating SignedData
 MUST correspond to the public key of an existing signature
 certificate unless an appropriate signature certificate does not yet
 exist, such as during initial enrollment.
 The encapsulating SignedData MUST be generated using SHA-384 and
 either ECDSA on P-384 or RSA using either RSASSA-PKCS1-v1_5 or
 RSASSA-PSS with an RSA-3072 or RSA-4096 key.
 If an appropriate signature certificate does not yet exist and if a
 Full PKI Request includes one or more certification requests and is
 authenticated using a shared-secret (because no appropriate
 certificate exists yet to authenticate the request), the Full PKI
 Request MUST be signed using the private key corresponding to the
 public key of one of the requested certificates.  When necessary
 (i.e., because there is no existing signature certificate and there
 is no signature certification request included), a Full PKI Request
 MAY be signed using a key pair intended for use in a key
 establishment certificate.  However, servers are not required to
 allow this behavior.

4.1. Tagged Certification Request

 The reqSequence tcr choice conveys PKCS #10 [RFC2986] syntax.  The
 CertificateRequest MUST comply with [RFC5272], Section 3.2.1.2.1,
 with the following additional requirements:
  • certificationRequestInfo:
  1. subjectPublicKeyInfo MUST be set as defined in Section 5.4 of

[RFC8603].

  1. Attributes:
       o  The ExtensionReq attribute MUST be included with its
          contents as follows:
          +  The keyUsage extension MUST be included, and it MUST be
             set as defined in [RFC8603].
          +  For rekey requests, the SubjectAltName extension MUST be
             included and set equal to the SubjectAltName of the
             certificate that is being used to sign the SignedData
             encapsulating the request (i.e., not the certificate
             being rekeyed) if the subject field of the certificate
             being used to generate the signature is NULL.
          +  Other extension requests MAY be included as desired.
       o  The ChangeSubjectName attribute, as defined in [RFC6402],
          MUST be included if the Full PKI Request encapsulating this
          Tagged Certification Request is being signed by a key for
          which a certificate currently exists and the existing
          certificate's subject field or SubjectAltName extension does
          not match the desired subject name or SubjectAltName
          extension of this certification request.
       o  The POP Link Witness Version 2 attribute MUST be included if
          the request is being authenticated using a shared-secret and
          the subject name in the certification request is NULL or
          otherwise does not uniquely identify the end-entity.  In the
          POP Link Witness Version 2 attribute, keyGenAlgorithm MUST
          be id-sha384 for certification requests, as defined in
          [RFC5754]; macAlgorithm MUST be HMAC-SHA384, as defined in
          [RFC4231].
  1. signatureAlgorithm MUST be ecdsa-with-sha384 for P-384

certification requests and sha384WithRSAEncryption or id-

       RSASSA-PSS for RSA-3072 and RSA-4096 certification requests.
  1. signature MUST be generated using the private key corresponding

to the public key in the CertificationRequestInfo for both

       signature and key establishment certification requests.  The
       signature provides proof-of-possession of the private key to
       the CA.

4.2. Certificate Request Message

 The reqSequence crm choice conveys Certificate Request Message Format
 (CRMF) [RFC4211] syntax.  The CertReqMsg MUST comply with [RFC5272],
 Section 3.2.1.2.2, with the following additional requirements:
  • popo MUST be included using the signature (POPOSigningKey) proof-

of-possession choice and be set as defined in [RFC4211],

    Section 4.1 for both signature and key establishment certification
    requests.  The POPOSigningKey poposkInput field MUST be omitted.
    The POPOSigningKey algorithmIdentifier MUST be ecdsa-with-sha384
    for P-384 certification requests and sha384WithRSAEncryption or
    id-RSASSA-PSS for RSA-3072 and RSA-4096 certification requests.
    The signature MUST be generated using the private key
    corresponding to the public key in the CertTemplate.
 The CertTemplate MUST comply with [RFC5272], Section 3.2.1.2.2, with
 the following additional requirements:
  • If version is included, it MUST be set to 2 as defined in

Section 5.3 of [RFC8603].

  • publicKey MUST be set as defined in Section 5.4 of [RFC8603].
  • Extensions:
  1. The keyUsage extension MUST be included, and it MUST be set as

defined in [RFC8603].

  1. For rekey requests, the SubjectAltName extension MUST be

included and set equal to the SubjectAltName of the certificate

       that is being used to sign the SignedData encapsulating the
       request (i.e., not the certificate being rekeyed) if the
       subject name of the certificate being used to generate the
       signature is NULL.
  1. Other extension requests MAY be included as desired.
  • Controls:
  1. The ChangeSubjectName attribute, as defined in [RFC6402], MUST

be included if the Full PKI Request encapsulating this Tagged

       Certification Request is being signed by a key for which a
       certificate currently exists and the existing certificate's
       subject name or SubjectAltName extension does not match the
       desired subject name or SubjectAltName extension of this
       certification request.
  1. The POP Link Witness Version 2 attribute MUST be included if

the request is being authenticated using a shared-secret and

       the subject name in the certification request is NULL or
       otherwise does not uniquely identify the end-entity.  In the
       POP Link Witness Version 2 attribute, keyGenAlgorithm MUST be
       id-sha384 for certification requests; macAlgorithm MUST be
       HMAC-SHA384 when keyGenAlgorithm is id-sha384.

5. RA Requirements

 This section addresses the optional case where one or more RAs act as
 intermediaries between clients and a CA as described in Section 7 of
 [RFC5272].  In this section, the term "client" refers to the entity
 from which the RA received the PKI Request.  This section is only
 applicable to RAs.

5.1. RA Processing of Requests

 RAs conforming to this document MUST ensure that only the permitted
 signature, hash, and MAC algorithms described throughout this profile
 are used in requests; if they are not, the RA MUST reject those
 requests.  The RA SHOULD return a CMCFailInfo with the value of
 badAlg [RFC5272].
 When processing end-entity-generated SignedData objects, RAs MUST NOT
 perform Cryptographic Message Syntax (CMS) Content Constraints (CCC)
 certificate extension processing [RFC6010].
 Other RA processing is performed as described in [RFC5272].

5.2. RA-Generated PKI Requests

 RAs mediate the certificate request process by collecting client
 requests in batches.  The RA MUST encapsulate client-generated PKI
 Requests in a new RA-signed PKI Request, it MUST create a Full PKI
 Request encapsulated in a SignedData, and the SignedData MUST be
 constructed in accordance with [RFC8755].  The PKIData content type
 complies with [RFC5272] with the following additional requirements:
  • controlSequence MUST be present. It MUST include the following

CMC controls: Transaction ID, Sender Nonce, and Batch Requests.

    Other appropriate CMC controls MAY be included.
  • cmsSequence MUST be present. It contains the original, unmodified

request(s) received from the client.

       SignedData (applied by the RA)
         PKIData
           controlSequence (Transaction ID, Sender Nonce,
                                                Batch Requests)
           cmsSequence
             SignedData (applied by client)
               PKIData
                 controlSequence (Transaction ID, Sender Nonce)
                 reqSequence
                   TaggedRequest
                   {TaggedRequest}
             {SignedData     (second client request)
               PKIData...}
 Authorization to sign RA-generated Full PKI Requests SHOULD be
 indicated in the RA certificate by inclusion of the id-kp-cmcRA
 Extended Key Usage (EKU) from [RFC6402].  The RA certificate MAY also
 include the CCC certificate extension [RFC6010], or it MAY indicate
 authorization through inclusion of the CCC certificate extension
 alone.  The RA certificate may also be authorized through the local
 configuration.
 If the RA is authorized via the CCC extension, then the CCC extension
 MUST include the object identifier for the PKIData content type.  CCC
 SHOULD be included if constraints are to be placed on the content
 types generated.
 The outer SignedData MUST be generated using SHA-384 and either ECDSA
 on P-384 or RSA using RSASSA-PKCS1-v1_5 or RSASSA-PSS with an
 RSA-3072 or RSA-4096 key.
 If the Full PKI Response is a successful response to a PKI Request
 that only contained a Get Certificate or Get CRL control, then the
 algorithm used in the response MUST match the algorithm used in the
 request.

5.3. RA-Generated PKI Responses

 In order for an RA certificate using the CCC certificate extension to
 be authorized to generate responses, the object identifier for the
 PKIResponse content type must be present in the CCC certificate
 extension.

6. CA Requirements

 This section specifies the requirements for CAs that receive PKI
 Requests and generate PKI Responses.

6.1. CA Processing of PKI Requests

 CAs conforming to this document MUST ensure that only the permitted
 signature, hash, and MAC algorithms described throughout this profile
 are used in requests; if they are not, the CA MUST reject those
 requests.  The CA SHOULD return a CMCStatusInfoV2 control with a
 CMCStatus of failed and a CMCFailInfo with the value of badAlg
 [RFC5272].
 For requests involving an RA (i.e., batched requests), the CA MUST
 verify the RA's authorization.  The following certificate fields MUST
 NOT be modifiable using the Modify Certification Request control:
 publicKey and the keyUsage extension.  The request MUST be rejected
 if an attempt to modify those certification request fields is
 present.  The CA SHOULD return a CMCStatusInfoV2 control with a
 CMCStatus of failed and a CMCFailInfo with a value of badRequest.
 When processing end-entity-generated SignedData objects, CAs MUST NOT
 perform CCC certificate extension processing [RFC6010].
 If a client-generated PKI Request includes the ChangeSubjectName
 attribute as described in Section 4.1 or 4.2 above, the CA MUST
 ensure that name change is authorized.  The mechanism for ensuring
 that the name change is authorized is out of scope.  A CA that
 performs this check and finds that the name change is not authorized
 MUST reject the PKI Request.  The CA SHOULD return an Extended CMC
 Status Info control (CMCStatusInfoV2) with a CMCStatus of failed.
 Other processing of PKIRequests is performed as described in
 [RFC5272].

6.2. CA-Generated PKI Responses

 CAs send PKI Responses to both client-generated requests and RA-
 generated requests.  If a Full PKI Response is returned in direct
 response to a client-generated request, it MUST be encapsulated in a
 SignedData, and the SignedData MUST be constructed in accordance with
 [RFC8755].
 If the PKI Response is in response to an RA-generated PKI Request,
 then the above PKI Response is encapsulated in another CA-generated
 PKI Response.  That PKI Response MUST be encapsulated in a
 SignedData, and the SignedData MUST be constructed in accordance with
 [RFC8755].  The above PKI Response is placed in the encapsulating PKI
 Response cmsSequence field.  The other fields are as above with the
 addition of the batch response control in controlSequence.  The
 following illustrates a successful CA response to an RA-encapsulated
 PKI Request, both of which include Transaction IDs and Nonces:
       SignedData (applied by the CA)
         PKIResponse
           controlSequence (Transaction ID, Sender Nonce, Recipient
                            Nonce, Batch Response)
           cmsSequence
             SignedData (applied by CA and includes returned
                         certificates)
               PKIResponse
                 controlSequence (Transaction ID, Sender Nonce,
                                  Recipient Nonce)
 The same private key used to sign certificates MUST NOT be used to
 sign Full PKI Response messages.  Instead, a separate certificate
 indicating authorization to sign CMC responses MUST be used.
 Authorization to sign Full PKI Responses SHOULD be indicated in the
 CA certificate by inclusion of the id-kp-cmcCA EKU from [RFC6402].
 The CA certificate MAY also include the CCC certificate extension
 [RFC6010], or it MAY indicate authorization through inclusion of the
 CCC certificate extension alone.  The CA certificate may also be
 authorized through local configuration.
 In order for a CA certificate using the CCC certificate extension to
 be authorized to generate responses, the object identifier for the
 PKIResponse content type must be present in the CCC certificate
 extension.  CCC SHOULD be included if constraints are to be placed on
 the content types generated.
 Signatures applied to individual certificates are as required in
 [RFC8603].
 The signature on the SignedData of a successful response to a client-
 generated request, or each individual inner SignedData on the
 successful response to an RA-generated request, MUST be generated
 using SHA-384 and either ECDSA on P-384 or RSA using RSASSA-
 PKCS1-v1_5 or RSASSA-PSS with an RSA-3072 or RSA-4096 key.  An
 unsuccessful response MUST be signed using the same key type and
 algorithm that signed the request.
 The outer SignedData on the Full PKI Response to any RA-generated PKI
 Request MUST be signed with the same key type and algorithm that
 signed the request.
 The SignedData on a successful Full PKI Response to a PKI Request
 that only contained a Get Certificate or Get CRL control MUST be
 signed with the same key type and algorithm that signed the request.

7. Client Requirements: Processing PKI Responses

 Clients conforming to this document MUST ensure that only the
 permitted signature, hash, and MAC algorithms described throughout
 this profile are used in responses; if they are not, the client MUST
 reject those responses.
 Clients MUST authenticate all Full PKI Responses.  This includes
 verifying that the PKI Response is signed by an authorized CA or RA
 whose certificate validates back to a trust anchor.  The authorized
 CA certificate MUST include the id-kp-cmcCA EKU and/or a CCC
 extension that includes the object identifier for the PKIResponse
 content type.  Otherwise, the CA is determined to be authorized to
 sign responses through an implementation-specific mechanism.  The PKI
 Response can be signed by an RA if it is an error message, if it is a
 response to a Get Certificate or Get CRL request, or if the PKI
 Response contains an inner PKI Response signed by a CA.  In the last
 case, each layer of PKI Response MUST still contain an authorized,
 valid signature signed by an entity with a valid certificate that
 verifies back to an acceptable trust anchor.  The authorized RA
 certificate MUST include the id-kp-cmcRA EKU and/or include a CCC
 extension that includes the object identifier for the PKIResponse
 content type.  Otherwise, the RA is determined to be authorized to
 sign responses through local configuration.
 When a newly issued certificate is included in the PKI Response, the
 client MUST verify that the newly issued certificate's public key
 matches the public key that the client requested.  The client MUST
 also ensure that the certificate's signature is valid and that the
 signature validates back to an acceptable trust anchor.
 Clients MUST reject PKI Responses that do not pass these tests.
 Local policy will determine whether the client returns a Full PKI
 Response with an Extended CMC Status Info control (CMCStatusInfoV2)
 with the CMCStatus set to failed to a user console, error log, or the
 server.
 If the Full PKI Response contains an Extended CMC Status Info control
 with a CMCStatus set to failed, then local policy will determine
 whether the client resends a duplicate certification request back to
 the server or an error state is returned to a console or error log.

8. Shared-Secrets

 When the Identity Proof V2 and POP Link Witness V2 controls are used,
 the shared-secret MUST be randomly generated and securely
 distributed.  The shared-secret MUST provide at least 192 bits of
 strength.

9. Security Considerations

 Protocol security considerations are found in [RFC2986], [RFC4211],
 [RFC8755], [RFC5272], [RFC5273], [RFC5274], [RFC8603], and [RFC6402].
 When CCC is used to authorize RA and CA certificates, then the
 security considerations in [RFC6010] also apply.  Algorithm security
 considerations are found in [RFC8755].
 Compliant with NIST Special Publication 800-57 [SP80057], this
 profile defines proof-of-possession of a key establishment private
 key by performing a digital signature.  Except for one-time proof-of-
 possession, a single key pair MUST NOT be used for both signature and
 key establishment.
 This specification requires implementations to generate key pairs and
 other random values.  The use of inadequate pseudorandom number
 generators (PRNGs) can result in little or no security.  The
 generation of quality random numbers is difficult.  NIST Special
 Publication 800-90A [SP80090A], FIPS 186-3 [FIPS186], and [RFC4086]
 offer random number generation guidance.
 When RAs are used, the list of authorized RAs MUST be securely
 distributed out of band to CAs.
 Presence of the POP Link Witness Version 2 and POP Link Random
 attributes protects against substitution attacks.
 The certificate policy for a particular environment will specify
 whether expired certificates can be used to sign certification
 requests.

10. IANA Considerations

 This document has no IANA actions.

11. References

11.1. Normative References

 [CNSA]     Committee on National Security Systems, "Use of Public
            Standards for Secure Information Sharing", CNSS Policy 15,
            October 2016,
            <https://www.cnss.gov/CNSS/issuances/Policies.cfm>.
 [FIPS186]  National Institute of Standards and Technology, "Digital
            Signature Standard (DSS)", DOI 10.6028/NIST.FIPS.186-4,
            FIPS PUB 186-4, July 2013,
            <http://nvlpubs.nist.gov/nistpubs/FIPS/
            NIST.FIPS.186-4.pdf>.
 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119,
            DOI 10.17487/RFC2119, March 1997,
            <https://www.rfc-editor.org/info/rfc2119>.
 [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
            Request Syntax Specification Version 1.7", RFC 2986,
            DOI 10.17487/RFC2986, November 2000,
            <https://www.rfc-editor.org/info/rfc2986>.
 [RFC4055]  Schaad, J., Kaliski, B., and R. Housley, "Additional
            Algorithms and Identifiers for RSA Cryptography for use in
            the Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile", RFC 4055,
            DOI 10.17487/RFC4055, June 2005,
            <https://www.rfc-editor.org/info/rfc4055>.
 [RFC4056]  Schaad, J., "Use of the RSASSA-PSS Signature Algorithm in
            Cryptographic Message Syntax (CMS)", RFC 4056,
            DOI 10.17487/RFC4056, June 2005,
            <https://www.rfc-editor.org/info/rfc4056>.
 [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
            "Randomness Requirements for Security", BCP 106, RFC 4086,
            DOI 10.17487/RFC4086, June 2005,
            <https://www.rfc-editor.org/info/rfc4086>.
 [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
            Certificate Request Message Format (CRMF)", RFC 4211,
            DOI 10.17487/RFC4211, September 2005,
            <https://www.rfc-editor.org/info/rfc4211>.
 [RFC4231]  Nystrom, M., "Identifiers and Test Vectors for HMAC-SHA-
            224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512",
            RFC 4231, DOI 10.17487/RFC4231, December 2005,
            <https://www.rfc-editor.org/info/rfc4231>.
 [RFC5272]  Schaad, J. and M. Myers, "Certificate Management over CMS
            (CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
            <https://www.rfc-editor.org/info/rfc5272>.
 [RFC5273]  Schaad, J. and M. Myers, "Certificate Management over CMS
            (CMC): Transport Protocols", RFC 5273,
            DOI 10.17487/RFC5273, June 2008,
            <https://www.rfc-editor.org/info/rfc5273>.
 [RFC5274]  Schaad, J. and M. Myers, "Certificate Management Messages
            over CMS (CMC): Compliance Requirements", RFC 5274,
            DOI 10.17487/RFC5274, June 2008,
            <https://www.rfc-editor.org/info/rfc5274>.
 [RFC5754]  Turner, S., "Using SHA2 Algorithms with Cryptographic
            Message Syntax", RFC 5754, DOI 10.17487/RFC5754, January
            2010, <https://www.rfc-editor.org/info/rfc5754>.
 [RFC6010]  Housley, R., Ashmore, S., and C. Wallace, "Cryptographic
            Message Syntax (CMS) Content Constraints Extension",
            RFC 6010, DOI 10.17487/RFC6010, September 2010,
            <https://www.rfc-editor.org/info/rfc6010>.
 [RFC6402]  Schaad, J., "Certificate Management over CMS (CMC)
            Updates", RFC 6402, DOI 10.17487/RFC6402, November 2011,
            <https://www.rfc-editor.org/info/rfc6402>.
 [RFC8017]  Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
            "PKCS #1: RSA Cryptography Specifications Version 2.2",
            RFC 8017, DOI 10.17487/RFC8017, November 2016,
            <https://www.rfc-editor.org/info/rfc8017>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
            2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
            May 2017, <https://www.rfc-editor.org/info/rfc8174>.
 [RFC8603]  Jenkins, M. and L. Zieglar, "Commercial National Security
            Algorithm (CNSA) Suite Certificate and Certificate
            Revocation List (CRL) Profile", RFC 8603,
            DOI 10.17487/RFC8603, May 2019,
            <https://www.rfc-editor.org/info/rfc8603>.
 [RFC8755]  Jenkins, M., "Using Commercial National Security Algorithm
            Suite Algorithms in Secure/Multipurpose Internet Mail
            Extensions", RFC 8755, DOI 10.17487/RFC8755, March 2020,
            <https://www.rfc-editor.org/info/rfc8755>.

11.2. Informative References

 [SP80057]  National Institute of Standards and Technology,
            "Recommendation for Key Management, Part 1: General",
            DOI 10.6028/NIST.SP.800-57pt1r4, Special
            Publication 800-57, Part 1, Revision 4, January 2016,
            <http://doi.org/10.6028/NIST.SP.800-57pt1r4>.
 [SP80059]  National Institute of Standards and Technology, "Guideline
            for Identifying an Information System as a National
            Security System", DOI 10.6028/NIST.SP.800-59, Special
            Publication 800-59, August 2003,
            <https://csrc.nist.gov/publications/detail/sp/800-59/
            final>.
 [SP80090A] National Institute of Standards and Technology,
            "Recommendation for Random Number Generation Using
            Deterministic Random Bit Generators",
            DOI 10.6028/NIST.SP.800-90Ar1, Special Publication
            800-90A Revision 1, June 2015,
            <http://doi.org/10.6028/NIST.SP.800-90Ar1>.

Appendix A. Scenarios

 This section illustrates several potential certificate enrollment and
 rekey scenarios supported by this profile.  This section does not
 intend to place any limits or restrictions on the use of CMC.

A.1. Initial Enrollment

 This section describes three scenarios for authenticating initial
 enrollment requests:
 1.  Previously certified signature key-pair (e.g., Manufacturer
     Installed Certificate).
 2.  Shared-secret distributed securely out of band.
 3.  RA authentication.

A.1.1. Previously Certified Signature Key-Pair

 In this scenario, the end-entity has a private signing key and a
 corresponding public key certificate obtained from a cryptographic
 module manufacturer recognized by the CA.  The end-entity signs a
 Full PKI Request with the private key that corresponds to the subject
 public key of the previously installed signature certificate.  The CA
 will verify the authorization of the previously installed certificate
 and issue an appropriate new certificate to the end-entity.

A.1.2. Shared-Secret Distributed Securely Out of Band

 In this scenario, the CA distributes a shared-secret out of band to
 the end-entity that the end-entity uses to authenticate its
 certification request.  The end-entity signs the Full PKI Request
 with the private key for which the certification is being requested.
 The end-entity includes the Identity Proof Version 2 control to
 authenticate the request using the shared-secret.  The CA uses either
 the Identification control or the subject name in the end-entity's
 enclosed PKCS #10 [RFC2986] or CRMF [RFC4211] certification request
 message to identify the request.  The end-entity performs either the
 POP Link Witness Version 2 mechanism as described in [RFC5272],
 Section 6.3.1.1 or the shared-secret/subject distinguished name
 linking mechanism as described in [RFC5272], Section 6.3.2.  The
 subject name in the enclosed PKCS #10 [RFC2986] or CRMF [RFC4211]
 certification request does not necessarily match the issued
 certificate, as it may be used just to help identify the request (and
 the corresponding shared-secret) to the CA.

A.1.3. RA Authentication

 In this scenario, the end-entity does not automatically authenticate
 its enrollment request to the CA, either because the end-entity has
 nothing to authenticate the request with or because the
 organizational policy requires an RA's involvement.  The end-entity
 creates a Full PKI Request and sends it to an RA.  The RA verifies
 the authenticity of the request.  If the request is approved, the RA
 encapsulates and signs the request as described in Section 4.2,
 forwarding the new request on to the CA.  The subject name in the
 PKCS #10 [RFC2986] or CRMF [RFC4211] certification request is not
 required to match the issued certificate; it may be used just to help
 identify the request to the RA and/or CA.

A.2. Rekey

 There are two scenarios to support the rekey of certificates that are
 already enrolled.  One addresses the rekey of signature certificates,
 and the other addresses the rekey of key establishment certificates.
 Typically, organizational policy will require certificates to be
 currently valid to be rekeyed, and it may require initial enrollment
 to be repeated when rekey is not possible.  However, some
 organizational policies might allow a grace period during which an
 expired certificate could be used to rekey.

A.2.1. Rekey of Signature Certificates

 When a signature certificate is rekeyed, the PKCS #10 [RFC2986] or
 CRMF [RFC4211] certification request message enclosed in the Full PKI
 Request will include the same subject name as the current signature
 certificate.  The Full PKI Request will be signed by the current
 private key corresponding to the current signature certificate.

A.2.2. Rekey of Key Establishment Certificates

 When a key establishment certificate is rekeyed, the Full PKI Request
 will generally be signed by the current private key corresponding to
 the current signature certificate.  If there is no current signature
 certificate, one of the initial enrollment options in Appendix A.1
 may be used.

Authors' Addresses

 Michael Jenkins
 National Security Agency
 Email: mjjenki@nsa.gov
 Lydia Zieglar
 National Security Agency
 Email: llziegl@tycho.ncsc.mil
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