DNS Extensions working group                             V.Dolmatov, Ed.  
Internet-Draft                                            Cryptocom Ltd.    
Intended status: Standards Track                      November 30, 2009
Expires: May 30, 2010                                 


 Use of GOST signature algorithms in DNSKEY and RRSIG Resource Records
                               for DNSSEC
                 draft-ietf-dnsext-dnssec-gost-05

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Abstract

   This document describes how to produce signature and hash using 
   GOST algorithms [DRAFT1, DRAFT2, DRAFT3] for DNSKEY, RRSIG and DS
   resource records for use in the Domain Name System Security 
   Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035).

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  DNSKEY Resource Records . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Using a public key with existing cryptographic libraries. . 3
     2.2.  GOST DNSKEY RR Example  . . . . . . . . . . . . . . . . . . 3
   3.  RRSIG Resource Records  . . . . . . . . . . . . . . . . . . . . 4
     3.1 RRSIG RR Example  . . . . . . . . . . . . . . . . . . . . . . 4
   4.  DS Resource Records . . . . . . . . . . . . . . . . . . . . . . 5
     4.1 DS RR Example . . . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Deployment Considerations . . . . . . . . . . . . . . . . . . . 5
     5.1.  Key Sizes . . . . . . . . . . . . . . . . . . . . . . . . . 5
     5.2.  Signature Sizes . . . . . . . . . . . . . . . . . . . . . . 5
     5.3.  Digest Sizes  . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Implementation Considerations . . . . . . . . . . . . . . . . . 5
     6.1.  Support for GOST signatures . . . . . . . . . . . . . . . . 5
     6.2.  Support for NSEC3 Denial of Existence . . . . . . . . . . . 5
     6.3.  Byte order  . . . . . . . . . . . . . . . . . . . . . . . . 5
   7. Security consideration . . . . . . . . . . . . . . . . . . . . . 5
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6
   10.  References   . . . . . . . . . . . . . . . . . . . . . . . . . 6
     10.1.  Normative References . . . . . . . . . . . . . . . . . . . 6
     10.2.  Informative References . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9

1.  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 [GOST3410, GOST3411],
   and specifies how to store DNSKEY data and how to produce
   RRSIG resource records with these hash algorithms.

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

   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].

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2.  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 
   {TBA1}.
      
   The wire format of the public key is compatible with 
   RFC 4491 [RFC4491]:

   According to [GOST3410], a public key is a point on the elliptic
   curve Q = (x,y).

   The wire representation of a public key MUST contain 66 octets, 
   where the first octet designates public key parameters, the second
   octet designates digest parameters next 32 octets contain the 
   little-endian representation of x and the second 32 octets contain
   the little-endian representation of y. 
   This corresponds to the binary representation of (<y>256||<x>256) 
   from [GOST3410], ch.  5.3.

   The only valid value for both parameters octets is 0.
   Other parameters octets values are reserved for future use.
   
   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].

2.1.  Using a public key with existing cryptographic libraries

   Existing GOST-aware cryptographic libraries at the time of this 
   document writing are capable to read 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 last 64 octets
   of key data (in other words, substitute first two parameter octets)
   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
  
2.2.  GOST DNSKEY RR Example

   Given a private key with the following value (the value of 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: {TBA1} (GOST)
   GostAsn1: MEUCAQAwHAYGKoUDAgITMBIGByqFAwICIwEGByqFAwICHgEEIgQgV/S
             2FXdMtzKJBehZvjF4lVSx6m66TwqSe/MFwKSH/3E=

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   The following DNSKEY RR stores a DNS zone key for example.net
 
   example.net. 86400 IN DNSKEY 256 3 {TBA1} (
                                AADMrbi2vAs4hklTmmzGE3WWNtJ8Dll0u0jq
                                tGRbNKeJguZQj/9EpGWmQK9hekPiPlzH2Ph6
                                yB7i836EfzmJo5LP
                                ) ; key id = 15820

3.  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].
   
   Hash MUST be calculated with GOST R 34.11-94 parameters identified
   by id-GostR3411-94-CryptoProParamSet [RFC4357].

   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."

3.1. 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
   should be created (assuming {TBA1}==249 until proper code is 
   assigned by IANA)

   www.example.net. 3600 IN RRSIG A {TBA1} 3 3600 20300101000000 (
                                  20000101000000 15820 example.net.
                                  2MIsZWtEx6pcfQrdl376B8sFg0qxsR8XMHpl
                                  jHh+V6U7Qte7WwI4C3Z1nFMRVf//C9rO2dGB
                                  rdp+C7wVoOHBqA== )
 
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  Note: Several GOST signatures calculated for the same message text 
   differ because of using of a random element is used in signature 
   generation process.

4.  DS Resource Records

   GOST R 34.11-94 digest algorithm is denoted in DS RRs by the digest
   type {TBA2}.The wire format of a digest value is compatible with 
   RFC4490 [RFC4490], that is 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].

4.1. DS RR Example

   For key signing key (assuming {TBA1}==249 until proper code is 
   assigned by IANA)

   example.net. 86400   DNSKEY  257 3 {TBA1} (
                                AAADr5vmKVdXo780hSRU1YZYWuMZUbEe9R7C
                                RRLc7Wj2osDXv2XbCnIpTUx8dVLnLKmDBquu
                                9tCz5oSsZl0cL0R2
                                ) ; key id = 21649

   The DS RR will be

   example.net. 3600 IN DS 21649 {TBA1} {TBA2} (
             A8146F448569F30B91255BA8E98DE14B18569A524C49593ADCA4103A
             A44649C6 )

5.  Deployment Considerations

5.1.  Key Sizes

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

5.2.  Signature Sizes

   According to the GOST signature algorithm specification [GOST3410],
   the size of a GOST signature is 512 bits.

5.3.  Digest Sizes

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

6.  Implementation Considerations

6.1.  Support for GOST signatures

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

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6.2.  Support for NSEC3 Denial of Existence

    Any DNSSEC-GOST implementation is required to have either NSEC or
    NSEC3 support.

6.3  Byte order

    Due to the fact that all existing industry implementations of GOST
    cryptographic libraries are returning GOST blobs in little-endian 
    format and in order to avoid the necessity for DNSSEC developers 
    to handle different cryptographic algorithms differently, it was
    chosen to send these blobs on the wire "as is" without 
    transformation of endianness.

7.  Security considerations

    Currently, the cryptographic resistance of the GOST 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 GOST 34.11-94 hash
    algorithm is estimated as 2**128 operations of computations of a
    step hash function. (There is 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).

8.  IANA Considerations

   This document updates the IANA registry "DNS Security Algorithm 
   Numbers [RFC4034]"
   (http://www.iana.org/assignments/dns-sec-alg-numbers).  
   The following entries are added to the registry:
                                     Zone    Trans.
   Value  Algorithm         Mnemonic Signing Sec.  References   Status
   {TBA1} GOST R 34.10-2001 GOST     Y       *     (this memo)  OPTIONAL

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

   Value   Algorithm        Status
   {TBA2}  GOST R 34.11-94  OPTIONAL

9. 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.

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   The following people provided additional feedback and text: Dmitry 
   Burkov, Jaap Akkerhuis, Olafur Gundmundsson, Jelte Jansen 
   and Wouter Wijngaards.


10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", RFC 2119, March 1997.

   [RFC3110]  Eastlake 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.

   [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
              the 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
              the Russia for Standards, 1994.  (In Russian)

   [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] S. Leontiev and G. Chudov, "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] S. Leontiev and D. Shefanovski, "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. 

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10.2.  Informative References

   [RFC4509]  Hardaker W., "Use of SHA-256 in DNSSEC Delegation Signer
              (DS) Resource Records (RRs)", RFC 4509, May 2006.

   [DRAFT1]   Dolmatov V., Kabelev D., Ustinov I., Vyshensky S.,
              "GOST R 34.10-2001 digital signature algorithm"
              draft-dolmatov-cryptocom-gost34102001-06, 11.10.09
              work in progress.


   [DRAFT2]   Dolmatov V., Kabelev D., Ustinov I., Vyshensky S.,
              "GOST R 34.11-94 Hash function algorithm"
              draft-dolmatov-cryptocom-gost341194-04, 11.10.09
              work in progress.

   [DRAFT3]   Dolmatov V., Kabelev D., Ustinov I., Emelyanova I.,
              "GOST 28147-89 encryption, decryption and MAC algorithms"
              draft-dolmatov-cryptocom-gost2814789-04, 11.10.09
              work in progress.

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Authors' Addresses


Vasily Dolmatov, Ed.
Cryptocom Ltd.
Kedrova 14, bld.2
Moscow, 117218, Russian Federation

EMail: dol@cryptocom.ru

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

EMail: ran@cryptocom.ru

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

EMail: igus@cryptocom.ru

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