Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 5940                                          IECA
Category: Standards Track                                     R. Housley
ISSN: 2070-1721                                           Vigil Security
                                                            August 2010


            Additional Cryptographic Message Syntax (CMS)
                    Revocation Information Choices

Abstract

  The Cryptographic Message Syntax (CMS) allows revocation information
  to be conveyed as part of the SignedData, EnvelopedData,
  AuthenticatedData, and AuthEnvelopedData content types.  The
  preferred format for revocation information is the Certificate
  Revocation List (CRL), but an extension mechanism supports other
  revocation information formats.  This document defines two additional
  revocation information formats for Online Certificate Status Protocol
  (OCSP) responses and Server-Based Certificate Validation Protocol
  (SCVP) requests and responses.

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 5741.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  http://www.rfc-editor.org/info/rfc5940.
















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Copyright Notice

  Copyright (c) 2010 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
  (http://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.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.

1.  Introduction

  The RevocationInfoChoices type defined in [CMS] provides a set of
  revocation status information alternatives, which allows revocation
  information to be conveyed as part of the SignedData, EnvelopedData,
  AuthenticatedData, and AuthEnvelopedData content types.  The intent
  is to provide information sufficient to determine whether the
  certificates and attribute certificates carried elsewhere in the CMS-
  protected content have been revoked.  There may be more revocation
  status information than necessary or there may be less revocation
  status information than necessary.

  X.509 Certificate Revocation Lists (CRLs) [PROFILE] are the primary
  source of revocation status information, but any other revocation
  information format can be supported.  This document specifies two
  other formats: Online Certificate Status Protocol (OCSP) responses
  [OCSP] and Server-Based Certificate Validation Protocol (SCVP)
  requests and responses [SCVP].

  Section 2 discusses the RevocationInformation structure.  Section 3
  defines a mechanism to carry OCSP responses.  Section 4 defines a
  mechanism to carry SCVP requests and responses.  Appendix A provides
  the normative ASN.1 syntax for the two mechanisms.

1.1.  Requirements Terminology

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
  document are to be interpreted as described in [WORDS].







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2.  Revocation Information

  For convenience, the ASN.1 definition of the RevocationInfoChoices
  type from [CMS] is repeated here:

  RevocationInfoChoices ::= SET OF RevocationInfoChoice

  RevocationInfoChoice ::= CHOICE {
    crl        CertificateList,
    other  [1] IMPLICIT OtherRevocationInfoFormat }

  OtherRevocationInfoFormat ::= SEQUENCE {
    otherRevInfoFormat  OBJECT IDENTIFIER,
    otherRevInfo        ANY DEFINED BY otherRevInfoFormat }

  The other CHOICE MUST be used to convey OCSP responses, SCVP
  requests, and SCVP responses.

  This document defines the id-ri arc under which the revocation
  information formats are defined.  The id-ri object identifier is:

  id-ri OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
    dod(6) internet(1) security(5) mechanisms(5) pkix(7) ri(16) }

  NOTE: Numbers 1 and 3 were assigned to CRL and Delta CRL.  These two
  numbers are not used because these formats use the
  RevocationInfoChoice crl CHOICE when included in CMS [CMS].

3.  OCSP Response

  To carry an OCSP response, the otherRevInfoFormat is set to
  id-ri-ocsp-response, which has the following ASN.1 definition:

  id-ri-ocsp-response OBJECT IDENTIFIER ::= { id-ri 2 }

  In this case, otherRevInfo MUST carry the OCSP response using the
  OCSPResponse type defined in [OCSP].  The responseStatus field MUST
  be successful and the responseBytes field MUST be present.

4.  SCVP Request and Response

  Unlike OSCP, SCVP permits unprotected and protected responses, where
  protected responses can be digitally signed or include message
  authentication codes.  While this provides more flexibility, it
  complicates implementations when an SCVP response can be validated by
  entities other than the entity that generated the SCVP request.  If a
  lower layer provides authentication and integrity for the client-
  server interaction and the response is not protected, then a third



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  party cannot validate the response because there is no way to know
  that the response was returned over a protected connection.  If a
  message authentication code is used, then the third party will be
  unable to validate the message authentication code because it does
  not possess the necessary private key.  For these reasons, SCVP
  responses sent to a third party MUST be signed by the SCVP server so
  that the third party can validate them.

  SCVP response validation requires matching it to the SCVP request.
  This means that the SCVP request MUST always be included with the
  response.  SCVP permits the client to retain the response, and SCVP
  permits the request to be returned in the response (in the requestReq
  field).  The request need not be protected for matching to be
  performed; nonces and certIds can be checked.

  To carry the SCVP request and response, the otherRevInfoFormat is set
  to id-ri-scvp, which has the following ASN.1 definition:

  id-ri-scvp OBJECT IDENTIFIER ::= { id-ri 4 }

  In this case, the otherRevInfo MUST carry both the SCVP request and
  response with the following structure:

  SCVPReqRes ::= SEQUENCE {
    request  [0] EXPLICIT ContentInfo OPTIONAL,
    response     ContentInfo }

  The SCVPReqRes has the following fields:

  o request contains the SCVP request.  It contains the unprotected
    request, authenticated request, or the signed request.  The request
    MUST be present if the response does not include the requestRef
    fullRequest field.

  o response contains the SCVP response.  It MUST contain the signed
    response.  Additionally, the responseStatus MUST be okay.
    Unprotected and authenticated responses MUST NOT be included.

5.  Security Considerations

  The security considerations of [CMS], [CMS-ASN], [OCSP], [SCVP], and
  [PROFILE-ASN] apply.

  To locally store unprotected or authenticated SCVP responses, a
  client can encapsulate the unprotected or authenticated SCVP response
  in a SignedData.  It is a matter of local policy whether these SCVP
  responses that are encapsulated and signed by the client are
  considered valid by another entity.



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6.  IANA Considerations

  This document makes use of object identifiers.  These object
  identifiers are defined in an arc delegated by IANA to the PKIX
  Working Group.  When the PKIX Working Group closes, this arc and its
  registration procedures will be transferred to IANA.  No further
  action by IANA is necessary for this document or any anticipated
  updates.

7.  References

7.1.  Normative References

  [CMS]     Housley, R., "Cryptographic Message Syntax (CMS)", RFC
            5652, September 2009.

  [CMS-ASN] Hoffman, P. and J. Schaad, "New ASN.1 Modules for
            Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
            June 2010.

  [OCSP]    Myers, M., Ankney, R., Malpani, A., Galperin, S., and C.
            Adams, "X.509 Internet Public Key Infrastructure Online
            Certificate Status Protocol - OCSP", RFC 2560, June 1999.

  [PROFILE-ASN]
            Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
            Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
            June 2010.

  [SCVP]    Freeman, T., Housley, R., Malpani, A., Cooper, D., and W.
            Polk, "Server-Based Certificate Validation Protocol
            (SCVP)", RFC 5055, December 2007.

  [WORDS]   Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997.

  [X.680]   ITU-T Recommendation X.680 (2002) | ISO/IEC 8824- 1:2002.
            Information Technology - Abstract Syntax Notation One.

  [X.681]   ITU-T Recommendation X.681 (2002) | ISO/IEC 8824- 2:2002.
            Information Technology - Abstract Syntax Notation One:
            Information Object Specification.

  [X.682]   ITU-T Recommendation X.682 (2002) | ISO/IEC 8824- 3:2002.
            Information Technology - Abstract Syntax Notation One:
            Constraint Specification.





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  [X.683]   ITU-T Recommendation X.683 (2002) | ISO/IEC 8824- 4:2002.
            Information Technology - Abstract Syntax Notation One:
            Parameterization of ASN.1 Specifications, 2002.

7.2.  Informative References

  [PROFILE] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
            Housley, R., and W. Polk, "Internet X.509 Public Key
            Infrastructure Certificate and Certificate Revocation List
            (CRL) Profile", RFC 5280, May 2008.









































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Appendix A.  ASN.1 Modules

  Appendix A.1 provides the normative ASN.1 definitions for the
  structures described in this specification using ASN.1 as defined in
  [X.680] for compilers that support the 1988 ASN.1.

  Appendix A.2 provides informative ASN.1 definitions for the
  structures described in this specification using ASN.1 as defined in
  [X.680], [X.681], [X.682], and [X.683] for compilers that support the
  2002 ASN.1. This appendix contains the same information as Appendix
  A.1 in a more recent (and precise) ASN.1 notation, however Appendix
  A.1 takes precedence in case of conflict.

A.1.  1988 ASN.1 Module

  CMS-Other-RIs-2009-88
    { iso(1) identified-organization(3) dod(6) internet(1) security(5)
      mechanisms(5) pkix(7) id-mod(0) id-mod-cms-otherRIs-2009-88(63)
    }

  DEFINITIONS IMPLICIT TAGS ::=

  BEGIN

  -- EXPORTS ALL
  IMPORTS

  -- FROM CMS [CMS]

  ContentInfo
    FROM CryptographicMessageSyntax2004
    { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
      smime(16) modules(0) cms-2004(24) }

  ;

  id-ri OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
    dod(6) internet(1) security(5) mechanisms(5) pkix(7) ri(16) }

  -- RevocationInfoChoice for OCSP response
  -- OID included in otherRevInfoFormat
  -- signed OCSP response included in otherRevInfo

  id-ri-ocsp-response OBJECT IDENTIFIER ::= { id-ri 2 }

  -- RevocationInfoChoice for SCVP response
  -- OID included in otherRevInfoFormat
  -- SCVPReqRes included in otherRevInfo



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  id-ri-scvp OBJECT IDENTIFIER ::= { id-ri 4 }

  SCVPReqRes ::= SEQUENCE {
    request  [0] EXPLICIT ContentInfo OPTIONAL,
    response     ContentInfo }

  END

A.2.  2002 ASN.1 Module

  CMS-Other-RIs-2009-02
    { iso(1) identified-organization(3) dod(6) internet(1) security(5)
      mechanisms(5) pkix(7) id-mod(0) id-mod-cms-otherRIs-2009-93(64)
    }

  DEFINITIONS IMPLICIT TAGS ::=

  BEGIN

  -- EXPORT ALL
  IMPORTS

  -- FROM [PROFILE-ASN]

  OCSPResponse
    FROM OCSP-2009
    { iso(1) identified-organization(3) dod(6) internet(1) security(5)
      mechanisms(5) pkix(7) id-mod(0) id-mod-ocsp-02(48) }

  -- FROM [CMS-ASN]

  ContentInfo, OTHER-REVOK-INFO
    FROM CryptographicMessageSyntax-2009
      { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
        smime(16) modules(0) id-mod-cms-2004-02(41) }

  ;

  -- Defines OCSP and SCVP formats for RevocationInfoChoice

  SupportedOtherRevokInfo OTHER-REVOK-INFO ::= {
    ri-ocsp-response |
    ri-scvp,
    ... }

  ri-ocsp-response OTHER-REVOK-INFO ::= {
    OCSPResponse IDENTIFIED BY id-ri-ocsp-response }




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  id-ri OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
    dod(6) internet(1) security(5) mechanisms(5) pkix(7) ri(16) }

  id-ri-ocsp-response OBJECT IDENTIFIER ::= { id-ri 2 }

  ri-scvp OTHER-REVOK-INFO ::= {
    SCVPReqRes IDENTIFIED BY id-ri-scvp }

  id-ri-scvp OBJECT IDENTIFIER ::= { id-ri 4 }

  SCVPReqRes ::= SEQUENCE {
    request  [0] EXPLICIT ContentInfo OPTIONAL,
    response     ContentInfo }

  END

Authors' Addresses

  Sean Turner
  IECA, Inc.
  3057 Nutley Street, Suite 106
  Fairfax, VA 22031
  USA

  EMail: [email protected]


  Russ Housley
  Vigil Security, LLC
  918 Spring Knoll Drive
  Herndon, VA 20170
  USA

  EMail: [email protected]

















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