DNS Extensions working group V.Dolmatov, Ed. Internet-Draft Cryptocom Ltd. Intended status: Standards Track December 12, 2009 Expires: June 12, 2010 Use of GOST signature algorithms in DNSKEY and RRSIG Resource Records for DNSSEC draft-ietf-dnsext-dnssec-gost-06 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 12 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. 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). V.Dolmatov Expires June 12, 2010 [Page 1] 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]. V.Dolmatov Expires June 12, 2010 [Page 2] 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 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. This corresponds to the binary representation of (256||256) from [GOST3410], ch. 5.3. 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 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 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: MEUCAQAwHAYGKoUDAgITMBIGByqFAwICIwEGByqFAwICHgEEIgQgp9c t2LQaNS1vMKPLEN9zHYjLPNMIQN6QB9vt3AghZFA= V.Dolmatov Expires June 12, 2010 [Page 3] The following DNSKEY RR stores a DNS zone key for example.net example.net. 86400 IN DNSKEY 256 3 {TBA1} ( GtTJjmZKUXV+lHLG/6crB6RCR+EJR51Islpa 6FqfT0MUfKhSn1yAo92+LJ0GDssTiAnj0H0I 9Jrfial/yyc5Og== ) ; key id = 10805 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 10805 example.net. k3m0r5bm6kFQmcRlHshY3jIj7KL6KTUsPIAp Vy466khKuWEUoVvSkqI+9tvMQySQgZcEmS0W HRFSm0XS5YST5g== ) V.Dolmatov Expires June 12, 2010 [Page 4] 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} ( 1aYdqrVz3JJXEURLMdmeI7H1CyTFfPVFBIGA EabZFP+7NT5KPYXzjDkRbPWleEFbBilDNQNi q/q4CwA4WR+ovg== ) ; key id = 6204 The DS RR will be example.net. 3600 IN DS 6204 {TBA1} {TBA2} ( 0E6D6CB303F89DBCF614DA6E21984F7A62D08BDD0A05B3A22CC63D1B 553BC61E ) 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. V.Dolmatov Expires June 12, 2010 [Page 5] 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. V.Dolmatov Expires June 12, 2010 [Page 6] 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. V.Dolmatov Expires June 12, 2010 [Page 7] 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-gost34102001-07, 12.12.09 work in progress. [DRAFT2] Dolmatov V., Kabelev D., Ustinov I., Vyshensky S., "GOST R 34.11-94 Hash function algorithm" draft-dolmatov-cryptocom-gost341194-06, 12.12.09 work in progress. [DRAFT3] Dolmatov V., Kabelev D., Ustinov I., Emelyanova I., "GOST 28147-89 encryption, decryption and MAC algorithms" draft-dolmatov-cryptocom-gost2814789-06, 12.12.09 work in progress. V.Dolmatov Expires June 12, 2010 [Page 8] 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 V.Dolmatov Expires June 12, 2010 [Page 9]