Independent Submission                                      B. Makarenko
Request for Comments: 9558         The Technical center of Internet, LLC
Category: Informational                                 V. Dolmatov, Ed.
ISSN: 2070-1721                                     JSC "NPK Kryptonite"
                                                             April 2024


  Use of GOST 2012 Signature Algorithms in DNSKEY and RRSIG Resource
                          Records for DNSSEC

Abstract

  This document describes how to produce digital signatures and hash
  functions using the GOST R 34.10-2012 and GOST R 34.11-2012
  algorithms for DNSKEY, RRSIG, and DS resource records, for use in the
  Domain Name System Security Extensions (DNSSEC).

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/rfc9558.

Copyright Notice

  Copyright (c) 2024 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.  DNSKEY Resource Records
    2.1.  Using a Public Key with Existing Cryptographic Libraries
    2.2.  GOST DNSKEY RR Example
  3.  RRSIG Resource Records
    3.1.  RRSIG RR Example
  4.  DS Resource Records
    4.1.  DS RR Example
  5.  Operational Considerations
    5.1.  Key Sizes
    5.2.  Signature Sizes
    5.3.  Digest Sizes
  6.  Implementation Considerations
  7.  IANA Considerations
  8.  Security Considerations
  9.  References
    9.1.  Normative References
    9.2.  Informative References
  Acknowledgments
  Authors' Addresses

1.  Introduction

  The Domain Name System (DNS) is the global, hierarchically
  distributed database for Internet Naming.  The DNS has been extended
  to use cryptographic keys and digital signatures for the verification
  of the authenticity and integrity of its data.  RFC 4033 [RFC4033],
  RFC 4034 [RFC4034], and RFC 4035 [RFC4035] describe these DNS
  Security Extensions, called DNSSEC.

  RFC 4034 describes how to store DNSKEY and RRSIG resource records and
  specifies a list of cryptographic algorithms to use.  This document
  extends that list with the signature and hash algorithms GOST R
  34.10-2012 ([RFC7091]) and GOST R 34.11-2012 ([RFC6986]), and it
  specifies how to store DNSKEY data and how to produce RRSIG resource
  records with these algorithms.

  GOST R 34.10-2012 and GOST R 34.11-2012 are Russian national
  standards.  Their cryptographic properties haven't been independently
  verified.

  Familiarity with DNSSEC and with GOST signature and hash algorithms
  is assumed in this document.

  Caution:

  This specification is not a standard and does not have IETF community
  consensus.  It makes use of a cryptographic algorithm that is a
  national standard for Russia.  Neither the IETF nor the IRTF has
  analyzed that algorithm for suitability for any given application,
  and it may contain either intended or unintended weaknesses.

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.

2.  DNSKEY Resource Records

  The format of the DNSKEY RR can be found in RFC 4034 [RFC4034].

  GOST R 34.10-2012 public keys are stored with the algorithm number
  23.

  According to RFC 7091 [RFC7091], a GOST R 34.10-2012 public key is a
  point on the elliptic curve Q = (x, y).  The wire representation of a
  public key MUST contain 64 octets, where the first 32 octets contain
  the little-endian representation of x and the second 32 octets
  contain the little-endian representation of y.

  As RFC 6986 and RFC 7091 allow two variants of the length of the
  output hash and the signature and many variants of parameters of the
  digital signature, for the purpose of this document we use the
  256-bit variant of the digital signature algorithm, corresponding
  with the 256-bit variant of the digest algorithm.  We select the
  parameters for the digital signature algorithm to be id-tc26-gost-
  3410-2012-256-paramSetA as specified in RFC 7836 [RFC7836]; this
  document refers to it as "parameter set A".

2.1.  Using a Public Key with Existing Cryptographic Libraries

  At the time of this writing, existing GOST-aware cryptographic
  libraries are capable of reading GOST R 34.10-2012 public keys via a
  generic X.509 API if the key is encoded according to RFC 9215
  [RFC9215], Section 4.

  To make this encoding from the wire format of a GOST R 34.10-2012
  public key with the parameters used in this document, prepend the 64
  octets of key data with the following 30-byte sequence:

  0x30 0x5c 0x30 0x17 0x06 0x08 0x2a 0x85
  0x03 0x07 0x01 0x01 0x01 0x01 0x30 0x0b
  0x06 0x09 0x2a 0x85 0x03 0x07 0x01 0x02
  0x01 0x01 0x01 0x03 0x41 0x00

  These bytes provide the following ASN.1 structure suitable for
  parsing by cryptographic toolkits:

    0  92: SEQUENCE {
    2  23:   SEQUENCE {
    4   8:     OBJECT IDENTIFIER '1 2 643 7 1 1 1 1'
   14  11:     SEQUENCE {
   16   9:       OBJECT IDENTIFIER '1 2 643 7 1 2 1 1 1'
         :       }
         :     }
   27  65:   BIT STRING

  The OIDs in the structure above represent a GOST R 34.10-2012 public
  key with a 256-bit private key length and parameter set A.  The
  structure itself represents SubjectPublicKeyInfo field of an X.509
  certificate as defined in RFC 5280 [RFC5280], Section 4.1

2.2.  GOST DNSKEY RR Example

  Given a private key with the following value:

  Private-key-format: v1.2
  Algorithm: 23 (ECC-GOST12)
  Gost12Asn1: MD4CAQAwFwYIKoUDBwEBAQEwCwYJKoUDBwECAQEBBCD/Mw9o6R5lQHJ13
              jz0W+C1tdsS4W7RJn04rk9MGJq3Hg==

  The following DNSKEY RR stores a DNS zone key for example:

  example.  600  IN  DNSKEY  256 3 23 (
              XGiiHlKUJd5fSeAK5O3L4tUNCPxs4pGqum6wKbqjdkqu
              IQ8nOXrilXZ9HcY8b2AETkWrtWHfwvJD4twPPJFQSA==
      ) ;{id = 47355 (zsk), size = 512b}

  The private key here is presented in PrivateKeyInfo ASN.1 structure,
  as described in RFC 5958 [RFC5958], Section 2.

  The public key can be calculated from the private key using algorithm
  described in RFC 7091 [RFC7091].

3.  RRSIG Resource Records

  The value of the signature field in the RRSIG RR follows RFC 7091
  [RFC7091] and is calculated as follows.  The values for the RDATA
  fields that precede the signature data are specified in RFC 4034
  [RFC4034].

  hash = GOSTR3411-2012(data)

  where "data" is the wire format data of the resource record set that
  is signed, as specified in RFC 4034 [RFC4034].

  The signature is calculated from the hash according to GOST R
  34.10-2012, and its wire format is compatible with RFC 7091
  [RFC7091].

3.1.  RRSIG RR Example

  Consider a given RRset consisting of one MX RR to be signed with the
  private key described in Section 2.2 of this document:

  example.  600  IN  MX  10 mail.example.

  Setting the inception date to 2022-10-06 12:32:30 UTC and the
  expiration date to 2022-11-03 12:32:30 UTC, the following signature
  RR will be valid:

  example.  600 IN  RRSIG MX 23 1 600 20221103123230 (
                         20221006123230 47355 example.
                         EuLO0Qpn6zT1pzj9T2H5AWjcgzfmjNiK/vj811bExa0V
                         HMOVD9ma8rpf0B+D+V4Q0CWu1Ayzu+H/SyndnOWGxw==
  )

  The GOST R 34.10-2012 signature algorithm uses random (pseudorandom)
  integer k as described in Section 6.1 of RFC 7091 [RFC7091].  The
  following value for k was used to produce the signature example.

  k = 8BBD0CE7CAF3FC1C2503DF30D13ED5DB75EEC44060FA22FB7E29628407C1E34

  This value for k MUST NOT be used when computing GOST R 34.10-2012
  signatures.  It is provided only so the above signature example can
  be reproduced.  The actual signature value will differ between
  signature calculations.

4.  DS Resource Records

  The GOST R 34.11-2012 digest algorithm is denoted in DS RRs by the
  digest type 5.  The wire format of a digest value is compatible with
  RFC 6986 [RFC6986].

4.1.  DS RR Example

  For Key Signing Key (KSK):

  example.  IN  DNSKEY  257 3 23 (
                         p8Req8DLJOfPymO5vExuK4gCcihF5N1YL7veCJ47av+w
                         h/qs9yJpD064k02rYUHfWnr7IjvJlbn3Z0sTZe9GRQ==
                         ) ;{id = 29468 (ksk), size = 512b}

  The DS RR will be:

  example.  IN  DS  29468 23 5 (
                        6033725b0ccfc05d1e9d844d49c6cf89
                        0b13d5eac9439189947d5db6c8d1c1ec
                        )

5.  Operational Considerations

5.1.  Key Sizes

  The key size of GOST R 34.10-2012 public keys conforming to this
  specification MUST be 512 bits according to RFC 7091 [RFC7091].

5.2.  Signature Sizes

  The size of a GOST R 34.10-2012 signature conforming to this
  specification MUST be 512 bits according to RFC 7091 [RFC7091].

5.3.  Digest Sizes

  The size of a GOST R 34.11-2012 digest conforming to this
  specification MUST be 256 bits according to RFC 6986 [RFC6986].

6.  Implementation Considerations

  The support of this cryptographic suite in DNSSEC-aware systems is
  OPTIONAL.  According to RFC 6840 [RFC6840], Section 5.2, systems that
  do not support these algorithms MUST ignore the RRSIG, DNSKEY, and DS
  resource records associated with the GOST R 34.10-2012 digital
  signature algorithm.

7.  IANA Considerations

  The following entry has been added to the IANA registry for "DNS
  Security Algorithm Numbers":

  +========+=============+============+=========+========+===========+
  | Number | Description | Mnemonic   | Zone    | Trans. | Reference |
  |        |             |            | Signing | Sec.   |           |
  +========+=============+============+=========+========+===========+
  | 23     | GOST R      | ECC-GOST12 | Y       | *      | RFC 9558  |
  |        | 34.10-2012  |            |         |        |           |
  +--------+-------------+------------+---------+--------+-----------+

                                Table 1

  The following entry has been added to the IANA registry for "Digest
  Algorithms" in the "Delegation Signer (DS) Resource Record (RR) Type
  Digest Algorithms" registry group:

          +=======+===================+==========+===========+
          | Value | Description       | Status   | Reference |
          +=======+===================+==========+===========+
          | 5     | GOST R 34.11-2012 | OPTIONAL | RFC 9558  |
          +-------+-------------------+----------+-----------+

                                Table 2

8.  Security Considerations

  It is recommended to use a dual KSK algorithm signed zone until GOST-
  aware DNSSEC software becomes more widespread, unless GOST-only
  cryptography is to be used.  Otherwise, GOST-signed zones may be
  considered unsigned by the DNSSEC software currently in use.

  Like all algorithms, it is possible that a significant flaw could be
  discovered with GOST R 34.11-2012.  In that case, deployments should
  roll over to another algorithm.  See RFC 7583 [RFC7583] on the timing
  of such changes.

9.  References

9.1.  Normative References

  [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>.

  [RFC3110]  Eastlake 3rd, D., "RSA/SHA-1 SIGs and RSA KEYs in the
             Domain Name System (DNS)", RFC 3110, DOI 10.17487/RFC3110,
             May 2001, <https://www.rfc-editor.org/info/rfc3110>.

  [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "DNS Security Introduction and Requirements",
             RFC 4033, DOI 10.17487/RFC4033, March 2005,
             <https://www.rfc-editor.org/info/rfc4033>.

  [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "Resource Records for the DNS Security Extensions",
             RFC 4034, DOI 10.17487/RFC4034, March 2005,
             <https://www.rfc-editor.org/info/rfc4034>.

  [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "Protocol Modifications for the DNS Security
             Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
             <https://www.rfc-editor.org/info/rfc4035>.

  [RFC6840]  Weiler, S., Ed. and D. Blacka, Ed., "Clarifications and
             Implementation Notes for DNS Security (DNSSEC)", RFC 6840,
             DOI 10.17487/RFC6840, February 2013,
             <https://www.rfc-editor.org/info/rfc6840>.

  [RFC6986]  Dolmatov, V., Ed. and A. Degtyarev, "GOST R 34.11-2012:
             Hash Function", RFC 6986, DOI 10.17487/RFC6986, August
             2013, <https://www.rfc-editor.org/info/rfc6986>.

  [RFC7091]  Dolmatov, V., Ed. and A. Degtyarev, "GOST R 34.10-2012:
             Digital Signature Algorithm", RFC 7091,
             DOI 10.17487/RFC7091, December 2013,
             <https://www.rfc-editor.org/info/rfc7091>.

  [RFC7583]  Morris, S., Ihren, J., Dickinson, J., and W. Mekking,
             "DNSSEC Key Rollover Timing Considerations", RFC 7583,
             DOI 10.17487/RFC7583, October 2015,
             <https://www.rfc-editor.org/info/rfc7583>.

  [RFC7836]  Smyshlyaev, S., Ed., Alekseev, E., Oshkin, I., Popov, V.,
             Leontiev, S., Podobaev, V., and D. Belyavsky, "Guidelines
             on the Cryptographic Algorithms to Accompany the Usage of
             Standards GOST R 34.10-2012 and GOST R 34.11-2012",
             RFC 7836, DOI 10.17487/RFC7836, March 2016,
             <https://www.rfc-editor.org/info/rfc7836>.

  [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>.

9.2.  Informative References

  [RFC4509]  Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer
             (DS) Resource Records (RRs)", RFC 4509,
             DOI 10.17487/RFC4509, May 2006,
             <https://www.rfc-editor.org/info/rfc4509>.

  [RFC5280]  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, DOI 10.17487/RFC5280, May 2008,
             <https://www.rfc-editor.org/info/rfc5280>.

  [RFC5933]  Dolmatov, V., Ed., Chuprina, A., and I. Ustinov, "Use of
             GOST Signature Algorithms in DNSKEY and RRSIG Resource
             Records for DNSSEC", RFC 5933, DOI 10.17487/RFC5933, July
             2010, <https://www.rfc-editor.org/info/rfc5933>.

  [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
             DOI 10.17487/RFC5958, August 2010,
             <https://www.rfc-editor.org/info/rfc5958>.

  [RFC9215]  Baryshkov, D., Ed., Nikolaev, V., and A. Chelpanov, "Using
             GOST R 34.10-2012 and GOST R 34.11-2012 Algorithms with
             the Internet X.509 Public Key Infrastructure", RFC 9215,
             DOI 10.17487/RFC9215, March 2022,
             <https://www.rfc-editor.org/info/rfc9215>.

Acknowledgments

  This document is a minor extension to RFC 4034 [RFC4034].  Also, we
  tried to follow the documents RFC 3110 [RFC3110], RFC 4509 [RFC4509],
  and RFC 5933 [RFC5933] for consistency.  The authors of and
  contributors to these documents are gratefully acknowledged for their
  hard work.

  The following people provided additional feedback, text, and valuable
  assistance: Alexander Venedyukhin, Michael StJohns, Valery Smyslov,
  Tim Wicinski, and Stéphane Bortzmeyer.

Authors' Addresses

  Boris Makarenko
  The Technical center of Internet, LLC
  8 marta St., 1, Bldg. 12
  Moscow
  127083
  Russian Federation
  Email: [email protected]


  Vasily Dolmatov (editor)
  JSC "NPK Kryptonite"
  Spartakovskaya Sq., 14, Bldg. 2
  Moscow
  105082
  Russian Federation
  Email: [email protected]

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