Commercial National Security Algorithm (CNSA) Suite Profile of Certificate Management over CMS
RFC 8756
| Document | Type |
RFC
- Informational
(March 2020)
Was
draft-jenkins-cnsa-cmc-profile
(individual)
|
|
|---|---|---|---|
| Authors | Michael J. Jenkins , Lydia Zieglar | ||
| Last updated | 2020-03-27 | ||
| RFC stream | Independent Submission | ||
| Formats | |||
| IETF conflict review | conflict-review-jenkins-cnsa-cmc-profile | ||
| Stream | ISE state | Published RFC | |
| Consensus boilerplate | Unknown | ||
| Document shepherd | Eliot Lear | ||
| Shepherd write-up | Show Last changed 2019-04-23 | ||
| IESG | IESG state | RFC 8756 (Informational) | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | Adrian Farrel <rfc-ise@rfc-editor.org> | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IANA Actions |
RFC 8756
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.
- TransactionId and SenderNonce SHOULD be included. Other CMC
controls MAY be included.
- 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]).
- 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:
- subjectPublicKeyInfo MUST be set as defined in Section 5.4 of
[RFC8603].
- 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].
- 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.
- 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:
- 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 name of the certificate being used to generate the
signature is NULL.
- Other extension requests MAY be included as desired.
* Controls:
- 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.
- 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