RFC5933

Internet Engineering Task Force (IETF) V. Dolmatov, Ed.Request for Comments: 5933 A. ChuprinaCategory: Standards Track I. UstinovISSN: 2070-1721 Cryptocom Ltd. July 2010

           Use of GOST 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 34.10-2001 and GOST R 34.11-94 algorithms for DNSKEY, RRSIG, and DS resource records, for use in the Domain Name System Security Extensions (DNSSEC).

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/rfc5933.

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.

Introduction

The Domain Name System (DNS) is the global hierarchical 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 34.10-2001 ([GOST3410], [RFC5832]) and GOST R 34.11-94 ([GOST3411], [RFC5831]), and specifies how to store DNSKEY data and how to produce RRSIG resource records with these algorithms.

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

The term "GOST" is not officially defined, but is usually used to refer to the collection of the Russian cryptographic algorithms GOST R 34.10-2001 [RFC5832], GOST R 34.11-94 [RFC5831], and

GOST 28147-89 [RFC5830]. Since GOST 28147-89 is not used in DNSSEC, "GOST" will only refer to GOST R 34.10-2001 and GOST R 34.11-94 in this document.

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 [RFC2119].

DNSKEY Resource Records

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

GOST R 34.10-2001 public keys are stored with the algorithm number 12.

The wire format of the public key is compatible with RFC 4491 [RFC4491]:

According to [GOST3410] and [RFC5832], a 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.

Corresponding public key parameters are those identified by id-GostR3410-2001-CryptoPro-A-ParamSet (1.2.643.2.2.35.1) [RFC4357], and the digest parameters are those identified by id-GostR3411-94-CryptoProParamSet (1.2.643.2.2.30.1) [RFC4357].

Using a Public Key with Existing Cryptographic Libraries

At the time of this writing, existing GOST-aware cryptographic libraries are capable of reading GOST public keys via a generic X509 API if the key is encoded according to RFC 4491 [RFC4491], Section 2.3.2.

To make this encoding from the wire format of a GOST public key with the parameters used in this document, prepend the 64 octets of key data with the following 37-byte sequence:

  0x30 0x63 0x30 0x1c 0x06 0x06 0x2a 0x85 0x03 0x02 0x02 0x13 0x30
  0x12 0x06 0x07 0x2a 0x85 0x03 0x02 0x02 0x23 0x01 0x06 0x07 0x2a
  0x85 0x03 0x02 0x02 0x1e 0x01 0x03 0x43 0x00 0x04 0x40

GOST DNSKEY RR Example

Given a private key with the following value (the value of the GostAsn1 field is split here into two lines to simplify reading; in the private key file, it must be in one line):

  Private-key-format: v1.2
  Algorithm: 12 (ECC-GOST)
  GostAsn1: MEUCAQAwHAYGKoUDAgITMBIGByqFAwICIwEGByqFAwICHgEEIgQg/9M
            iXtXKg9FDXDN/R9CmVhJDyuzRAIgh4tPwCu4NHIs=

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

  example.net. 86400 IN DNSKEY 256 3 12 (
                               aRS/DcPWGQj2wVJydT8EcAVoC0kXn5pDVm2I
                               MvDDPXeD32dsSKcmq8KNVzigjL4OXZTV+t/6
                               w4X1gpNrZiC01g==
                               ) ; key id = 59732

RRSIG Resource Records

The value of the signature field in the RRSIG RR follows RFC 4490 [RFC4490] and is calculated as follows. The values for the RDATA fields that precede the signature data are specified in RFC 4034 [RFC4034].

hash = GOSTR3411(data)

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

The hash MUST be calculated with GOST R 34.11-94 parameters identified by id-GostR3411-94-CryptoProParamSet [RFC4357].

The signature is calculated from the hash according to the GOST R 34.10-2001 standard, and its wire format is compatible with RFC 4490 [RFC4490].

Quoting RFC 4490:

"The signature algorithm GOST R 34.10-2001 generates a digital signature in the form of two 256-bit numbers, r and s. Its octet string representation consists of 64 octets, where the first 32 octets contain the big-endian representation of s and the second 32 octets contain the big-endian representation of r".

RRSIG RR Example

With the private key from Section 2.2, sign the following RRSet, consisting of one A record:

  www.example.net. 3600 IN A 192.0.2.1

Setting the inception date to 2000-01-01 00:00:00 UTC and the expiration date to 2030-01-01 00:00:00 UTC, the following signature RR will be valid:

 www.example.net. 3600 IN RRSIG A 12 3 3600 20300101000000 (
                                20000101000000 59732 example.net.
                                7vzzz6iLOmvtjs5FjVjSHT8XnRKFY15ki6Kp
                                kNPkUnS8iIns0Kv4APT+D9ibmHhGri6Sfbyy
                                zi67+wBbbW/jrA== )

Note: The ECC-GOST signature algorithm uses random data, so the actual computed signature value will differ between signature calculations.

DS Resource Records

The GOST R 34.11-94 digest algorithm is denoted in DS RRs by the digest type 3. The wire format of a digest value is compatible with RFC 4490 [RFC4490], that is, the digest is in little-endian representation.

The digest MUST always be calculated with GOST R 34.11-94 parameters identified by id-GostR3411-94-CryptoProParamSet [RFC4357].

DS RR Example

For Key Signing Key (KSK):

  example.net. 86400   DNSKEY  257 3 12 (
                               LMgXRHzSbIJGn6i16K+sDjaDf/k1o9DbxScO
                               gEYqYS/rlh2Mf+BRAY3QHPbwoPh2fkDKBroF
                               SRGR7ZYcx+YIQw==
                               ) ; key id = 40692

The DS RR will be

  example.net. 3600 IN DS 40692 12 3 (
            22261A8B0E0D799183E35E24E2AD6BB58533CBA7E3B14D659E9CA09B
            2071398F )

Deployment Considerations

Key Sizes

According to RFC 4357 [RFC4357], the key size of GOST public keys MUST be 512 bits.

Signature Sizes

According to the GOST R 34.10-2001 digital signature algorithm specification ([GOST3410], [RFC5832]), the size of a GOST signature is 512 bits.

Digest Sizes

According to GOST R 34.11-94 ([GOST3411], [RFC5831]), the size of a GOST digest is 256 bits.

Implementation Considerations

Support for GOST Signatures

DNSSEC-aware implementations MAY be able to support RRSIG and DNSKEY resource records created with the GOST algorithms as defined in this document.

Support for NSEC3 Denial of Existence

Any DNSSEC-GOST implementation MUST support both NSEC [RFC4035] and NSEC3 [RFC5155].

Security Considerations

Currently, the cryptographic resistance of the GOST R 34.10-2001 digital signature algorithm is estimated as 2**128 operations of multiple elliptic curve point computations on prime modulus of order 2**256.

Currently, the cryptographic resistance of the GOST R 34.11-94 hash algorithm is estimated as 2**128 operations of computations of a step hash function. (There is a known method to reduce this estimate to 2**105 operations, but it demands padding the colliding message with 1024 random bit blocks each of 256-bit length; thus, it cannot be used in any practical implementation).

IANA Considerations

This document updates the IANA registry "DNS Security Algorithm Numbers" [RFC4034]. The following entries have been added to the registry:

                                  Zone    Trans.
Value  Algorithm         Mnemonic Signing Sec.  References   Status
 12    GOST R 34.10-2001 ECC-GOST     Y   *     RFC 5933    OPTIONAL

This document updates the RFC 4034 Digest Types assignment ([RFC4034], Section A.2) by adding the value and status for the GOST R 34.11-94 algorithm:

  Value   Algorithm        Status
    3    GOST R 34.11-94  OPTIONAL

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 4357 [RFC4357] 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: Dmitry Burkov, Jaap Akkerhuis, Olafur Gundmundsson, Jelte Jansen, and Wouter Wijngaards.

References

Normative References

[GOST3410] "Information technology. Cryptographic data security. Signature and verification processes of [electronic] digital signature.", GOST R 34.10-2001, Gosudarstvennyi Standard of Russian Federation, Government Committee of Russia for Standards, 2001. (In Russian). [GOST3411] "Information technology. Cryptographic data security. Hashing function.", GOST R 34.11-94, Gosudarstvennyi Standard of Russian Federation, Government Committee of Russia for Standards, 1994. (In Russian). [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC3110] Eastlake 3rd, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)", RFC 3110, May 2001. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, March 2005. [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [RFC4357] Popov, V., Kurepkin, I., and S. Leontiev, "Additional Cryptographic Algorithms for Use with GOST 28147-89, GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms", RFC 4357, January 2006. [RFC4490] Leontiev, S., Ed. and G. Chudov, Ed., "Using the GOST 28147-89, GOST R 34.11-94, GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS)", RFC 4490, May 2006. [RFC4491] Leontiev, S., Ed. and D. Shefanovski, Ed., "Using the GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms with the Internet X.509 Public Key Infrastructure Certificate and CRL Profile", RFC 4491, May 2006. [RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS Security (DNSSEC) Hashed Authenticated Denial of Existence", RFC 5155, March 2008.

Informative References

[RFC4509] Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer (DS) Resource Records (RRs)", RFC 4509, May 2006. [RFC5830] Dolmatov, V., Ed., "GOST 28147-89: Encryption, Decryption, and Message Authentication Code (MAC) Algorithms", RFC 5830, March 2010. [RFC5831] Dolmatov, V., Ed., "GOST R 34.11-94: Hash Function Algorithm", RFC 5831, March 2010.

[RFC5832] Dolmatov, V., Ed., "GOST R 34.10-2001: Digital Signature Algorithm", RFC 5832, March 2010. Authors' Addresses

Vasily Dolmatov (editor) Cryptocom Ltd. 14/2, Kedrova St. Moscow, 117218 Russian Federation

Phone: +7 499 124 6226 EMail: [email protected]

Artem Chuprina Cryptocom Ltd. 14/2, Kedrova St. Moscow, 117218 Russian Federation

Phone: +7 499 124 6226 EMail: [email protected]

Igor Ustinov Cryptocom Ltd. 14/2, Kedrova St. Moscow, 117218 Russian Federation

Phone: +7 499 124 6226 EMail: [email protected]