



Internet Engineering Task Force (IETF)                        R. Housley
Request for Comments: 9169                                Vigil Security
Category: Informational                                       C. Wallace
ISSN: 2070-1721                                       Red Hound Software
                                                           December 2021


         New ASN.1 Modules for the Evidence Record Syntax (ERS)

Abstract

   The Evidence Record Syntax (ERS) and the conventions for including
   these evidence records in the Server-based Certificate Validation
   Protocol (SCVP) are expressed using ASN.1.  This document offers
   alternative ASN.1 modules that conform to the 2002 version of ASN.1
   and employ the conventions adopted in RFCs 5911, 5912, and 6268.
   There are no bits-on-the-wire changes to any of the formats; this is
   simply a change to the ASN.1 syntax.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are 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/rfc9169.

Copyright Notice

   Copyright (c) 2021 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
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   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  ASN.1 Module for RFC 4998
   3.  ASN.1 Module for RFC 5276
   4.  IANA Considerations
   5.  Security Considerations
   6.  References
     6.1.  Normative References
     6.2.  Informative References
   Authors' Addresses

1.  Introduction

   Some developers would like the IETF to use the latest version of
   ASN.1 in its standards.  This document provides alternative ASN.1
   modules to assist in that goal.

   The Evidence Record Syntax (ERS) [RFC4998] provides two ASN.1
   modules: one using the 1988 syntax [OLD-ASN1], which has been
   deprecated by the ITU-T, and another one using the newer syntax
   [NEW-ASN1], which continues to be maintained and enhanced.  This
   document provides an alternative ASN.1 module that follows the
   conventions established in [RFC5911], [RFC5912], and [RFC6268].

   In addition, [RFC5276] specifies the mechanism for conveying evidence
   records in the Server-based Certificate Validation Protocol (SCVP)
   [RFC5055].  There is only one ASN.1 module in [RFC5276], and it uses
   the 1988 syntax [OLD-ASN1].  This document provides an alternative
   ASN.1 module using the newer syntax [NEW-ASN1] and follows the
   conventions established in [RFC5911], [RFC5912], and [RFC6268].  Note
   that [RFC5912] already includes an alternative ASN.1 module for SCVP
   [RFC5055].

   The original ASN.1 modules get some of their definitions from places
   outside the RFC series.  Some of the referenced definitions are
   somewhat difficult to find.  The alternative ASN.1 modules offered in
   this document stand on their own when combined with the modules in
   [RFC5911], [RFC5912], and [RFC6268].

   The alternative ASN.1 modules produce the same bits on the wire as
   the original ones.

   The alternative ASN.1 modules are informative; the original ones are
   normative.

2.  ASN.1 Module for RFC 4998

   <CODE BEGINS>
      ERS-2021
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) ltans(11) id-mod(0)
          id-mod-ers(1) id-mod-ers-v2(2) }

      DEFINITIONS IMPLICIT TAGS ::=
      BEGIN

      EXPORTS ALL;

      IMPORTS

      ContentInfo
        FROM CryptographicMessageSyntax-2010 -- in [RFC6268]
          { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
            pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) }

      AlgorithmIdentifier{}, DIGEST-ALGORITHM
        FROM AlgorithmInformation-2009 -- in [RFC5912]
          { iso(1) identified-organization(3) dod(6) internet(1)
            security(5) mechanisms(5) pkix(7) id-mod(0)
            id-mod-algorithmInformation-02(58) }

      AttributeSet{}, ATTRIBUTE
        FROM PKIX-CommonTypes-2009 -- in [RFC5912]
          { iso(1) identified-organization(3) dod(6) internet(1)
            security(5) mechanisms(5) pkix(7) id-mod(0)
            id-mod-pkixCommon-02(57) }
      ;

      ltans OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
        dod(6) internet(1) security(5) mechanisms(5) ltans(11) }

      EvidenceRecord ::= SEQUENCE {
        version  INTEGER { v1(1) },
        digestAlgorithms  SEQUENCE OF AlgorithmIdentifier
                            {DIGEST-ALGORITHM, {...}},
        cryptoInfos  [0] CryptoInfos OPTIONAL,
        encryptionInfo  [1] EncryptionInfo OPTIONAL,
        archiveTimeStampSequence  ArchiveTimeStampSequence }

      CryptoInfos ::= SEQUENCE SIZE (1..MAX) OF Attribute

      ArchiveTimeStamp ::= SEQUENCE {
        digestAlgorithm [0] AlgorithmIdentifier
                              {DIGEST-ALGORITHM, {...}} OPTIONAL,
        attributes      [1] Attributes OPTIONAL,
        reducedHashtree [2] SEQUENCE OF PartialHashtree OPTIONAL,
        timeStamp       ContentInfo }

      PartialHashtree ::= SEQUENCE OF OCTET STRING

      Attributes ::= SET SIZE (1..MAX) OF Attribute

      ArchiveTimeStampChain ::= SEQUENCE OF ArchiveTimeStamp

      ArchiveTimeStampSequence ::= SEQUENCE OF ArchiveTimeStampChain

      EncryptionInfo ::= SEQUENCE {
        encryptionInfoType  ENCINFO-TYPE.&id
          ({SupportedEncryptionAlgorithms}),
        encryptionInfoValue  ENCINFO-TYPE.&Type
          ({SupportedEncryptionAlgorithms}{@encryptionInfoType}) }

      ENCINFO-TYPE ::= TYPE-IDENTIFIER

      SupportedEncryptionAlgorithms ENCINFO-TYPE ::= { ... }

      aa-er-internal ATTRIBUTE ::=
        { TYPE EvidenceRecord IDENTIFIED BY id-aa-er-internal }

      id-aa-er-internal  OBJECT IDENTIFIER ::= { iso(1) member-body(2)
        us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 49 }

      aa-er-external ATTRIBUTE ::=
        { TYPE EvidenceRecord IDENTIFIED BY id-aa-er-external }

      id-aa-er-external  OBJECT IDENTIFIER ::= { iso(1) member-body(2)
        us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 50 }

      ERSAttrSet ATTRIBUTE ::= { aa-er-internal | aa-er-external, ... }

      Attribute ::= AttributeSet {{ERSAttrSet}}

      END
   <CODE ENDS>

3.  ASN.1 Module for RFC 5276

   <CODE BEGINS>
      LTANS-SCVP-EXTENSION-2021
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) ltans(11) id-mod(0)
          id-mod-ers-scvp(5) id-mod-ers-scvp-v2(2) }

      DEFINITIONS IMPLICIT TAGS ::=
      BEGIN

      EXPORTS ALL;

      IMPORTS

      id-swb, CertBundle, WANT-BACK, AllWantBacks
        FROM SCVP-2009 -- in [RFC5912]
          { iso(1) identified-organization(3) dod(6) internet(1)
            security(5) mechanisms(5) pkix(7) id-mod(0)
            id-mod-scvp-02(52) }

      EvidenceRecord
        FROM ERS-2021 -- in [RFC9169]
          { iso(1) identified-organization(3) dod(6) internet(1)
            security(5) mechanisms(5) ltans(11) id-mod(0)
            id-mod-ers(1) id-mod-ers-v2(2) }
     ;

      EvidenceRecordWantBack ::= SEQUENCE {
        targetWantBack  WANT-BACK.&id ({ExpandedWantBacks}),
        evidenceRecord  EvidenceRecord OPTIONAL }

      EvidenceRecordWantBacks ::= SEQUENCE SIZE (1..MAX) OF
                                    EvidenceRecordWantBack

      EvidenceRecords ::= SEQUENCE SIZE (1..MAX) OF EvidenceRecord

      ExpandedWantBacks WANT-BACK ::= { AllWantBacks |
                                        NewWantBacks |
                                        ERSWantBacks, ... }

      NewWantBacks WANT-BACK ::= { swb-partial-cert-path, ... }

      swb-partial-cert-path WANT-BACK ::=
        { CertBundle IDENTIFIED BY id-swb-partial-cert-path }

      id-swb-partial-cert-path OBJECT IDENTIFIER ::= { id-swb 15 }

      ERSWantBacks WANT-BACK ::= { swb-ers-pkc-cert |
                                   swb-ers-best-cert-path |
                                   swb-ers-partial-cert-path |
                                   swb-ers-revocation-info |
                                   swb-ers-all, ... }

      swb-ers-pkc-cert WANT-BACK ::=
        { EvidenceRecord IDENTIFIED BY id-swb-ers-pkc-cert }

      id-swb-ers-pkc-cert OBJECT IDENTIFIER ::= { id-swb 16 }

      swb-ers-best-cert-path WANT-BACK ::=
        { EvidenceRecord IDENTIFIED BY id-swb-ers-best-cert-path }

      id-swb-ers-best-cert-path OBJECT IDENTIFIER ::= { id-swb 17 }

      swb-ers-partial-cert-path WANT-BACK ::=
        { EvidenceRecord IDENTIFIED BY id-swb-ers-partial-cert-path }

      id-swb-ers-partial-cert-path OBJECT IDENTIFIER ::= { id-swb 18 }

      swb-ers-revocation-info WANT-BACK ::=
        { EvidenceRecords IDENTIFIED BY id-swb-ers-revocation-info }

      id-swb-ers-revocation-info OBJECT IDENTIFIER ::= { id-swb 19 }

      swb-ers-all WANT-BACK ::=
        { EvidenceRecordWantBacks IDENTIFIED BY id-swb-ers-all }

      id-swb-ers-all OBJECT IDENTIFIER ::= { id-swb 20 }

      END
   <CODE ENDS>

4.  IANA Considerations

   IANA has assigned two object identifiers from the "SMI Security for
   LTANS Module Identifier" registry to identify the two ASN.1 modules
   in this document.

   The following object identifiers have been assigned:

         +======================+====================+===========+
         | OID Value            | Description        | Reference |
         +======================+====================+===========+
         | 1.3.6.1.5.5.11.0.1.2 | id-mod-ers-v2      | RFC 9169  |
         +----------------------+--------------------+-----------+
         | 1.3.6.1.5.5.11.0.5.2 | id-mod-ers-scvp-v2 | RFC 9169  |
         +----------------------+--------------------+-----------+

                      Table 1: IANA Object Identifiers

5.  Security Considerations

   Please see the security considerations in [RFC4998] and [RFC5276].
   This document makes no changes to the security considerations in
   those documents.  The ASN.1 modules in this document preserve bits on
   the wire as the ASN.1 modules that they replace.

6.  References

6.1.  Normative References

   [NEW-ASN1] ITU-T, "Information technology -- Abstract Syntax Notation
              One (ASN.1): Specification of basic notation", ITU-T
              Recommendation X.680, ISO/IEC 8824-1:2021, February 2021,
              <https://www.itu.int/rec/T-REC-X.680>.

   [RFC4998]  Gondrom, T., Brandner, R., and U. Pordesch, "Evidence
              Record Syntax (ERS)", RFC 4998, DOI 10.17487/RFC4998,
              August 2007, <https://www.rfc-editor.org/info/rfc4998>.

   [RFC5055]  Freeman, T., Housley, R., Malpani, A., Cooper, D., and W.
              Polk, "Server-Based Certificate Validation Protocol
              (SCVP)", RFC 5055, DOI 10.17487/RFC5055, December 2007,
              <https://www.rfc-editor.org/info/rfc5055>.

   [RFC5276]  Wallace, C., "Using the Server-Based Certificate
              Validation Protocol (SCVP) to Convey Long-Term Evidence
              Records", RFC 5276, DOI 10.17487/RFC5276, August 2008,
              <https://www.rfc-editor.org/info/rfc5276>.

   [RFC5911]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for
              Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
              DOI 10.17487/RFC5911, June 2010,
              <https://www.rfc-editor.org/info/rfc5911>.

   [RFC5912]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
              Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
              DOI 10.17487/RFC5912, June 2010,
              <https://www.rfc-editor.org/info/rfc5912>.

   [RFC6268]  Schaad, J. and S. Turner, "Additional New ASN.1 Modules
              for the Cryptographic Message Syntax (CMS) and the Public
              Key Infrastructure Using X.509 (PKIX)", RFC 6268,
              DOI 10.17487/RFC6268, July 2011,
              <https://www.rfc-editor.org/info/rfc6268>.

6.2.  Informative References

   [OLD-ASN1] CCITT, "Specification of Abstract Syntax Notation One
              (ASN.1)", CCITT Recommendation X.208, November 1988,
              <https://www.itu.int/rec/T-REC-X.208/en>.

Authors' Addresses

   Russ Housley
   Vigil Security, LLC
   516 Dranesville Road
   Herndon, VA 20170
   United States of America

   Email: housley@vigilsec.com


   Carl Wallace
   Red Hound Software, Inc.
   5112 27th St. N
   Arlington, VA 22207
   United States of America

   Email: carl@redhoundsoftware.com
