393 lines
11 KiB
Plaintext
393 lines
11 KiB
Plaintext
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DNS Extensions working group J. Jansen
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Internet-Draft NLnet Labs
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Expires: July 5, 2006 January 2006
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Use of RSA/SHA-256 DNSKEY and RRSIG Resource Records in DNSSEC
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draft-ietf-dnsext-dnssec-rsasha256-00
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Status of this Memo
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By submitting this Internet-Draft, each author represents that any
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applicable patent or other IPR claims of which he or she is aware
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have been or will be disclosed, and any of which he or she becomes
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aware will be disclosed, in accordance with Section 6 of BCP 79.
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Internet-Drafts are working documents of the Internet Engineering
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Task Force (IETF), its areas, and its working groups. Note that
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other groups may also distribute working documents as Internet-
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Drafts.
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Internet-Drafts are draft documents valid for a maximum of six months
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and may be updated, replaced, or obsoleted by other documents at any
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time. It is inappropriate to use Internet-Drafts as reference
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material or to cite them other than as "work in progress."
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The list of current Internet-Drafts can be accessed at
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http://www.ietf.org/ietf/1id-abstracts.txt.
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The list of Internet-Draft Shadow Directories can be accessed at
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http://www.ietf.org/shadow.html.
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This Internet-Draft will expire on July 5, 2006.
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Copyright Notice
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Copyright (C) The Internet Society (2006).
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Abstract
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This document describes how to produce RSA/SHA-256 DNSKEY and RRSIG
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resource records for use in the Domain Name System Security
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Extensions (DNSSEC, RFC4033, RFC4034, and RFC4035).
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Jansen Expires July 5, 2006 [Page 1]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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Table of Contents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
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2. RSA/SHA-256 DNSKEY Resource Records . . . . . . . . . . . . . . 3
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3. RSA/SHA-256 RRSIG Resource Records . . . . . . . . . . . . . . 3
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4. Implementation Considerations . . . . . . . . . . . . . . . . . 4
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5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
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6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
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7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
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8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
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8.2. Informative References . . . . . . . . . . . . . . . . . . 5
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Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
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Intellectual Property and Copyright Statements . . . . . . . . . . 7
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Jansen Expires July 5, 2006 [Page 2]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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1. Introduction
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The Domain Name System (DNS) is the global hierarchical distributed
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database for Internet Addressing. The DNS has been extended to use
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digital signatures and cryptographic keys for the verification of
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data. RFC4033 [1], RFC4034 [2], and RFC4035 [3] describe these DNS
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Security Extensions.
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RFC4034 describes how to store DNSKEY and RRSIG resource records, and
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specifies a list of cryptographic algorithms to use. This document
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extends that list with the algorithm RSA/SHA-256, and specifies how
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to store RSA/SHA-256 DNSKEY data and how to produce RSA/SHA-256 RRSIG
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resource records.
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Familiarity with the RSA [7] and SHA-256 [5] algorithms is assumed in
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this document.
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2. RSA/SHA-256 DNSKEY Resource Records
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RSA public keys for use with RSA/SHA-256 are stored in DNSKEY
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resource records (RRs) with the algorithm number [TBA].
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The format of the DNSKEY RR can be found in RFC4034 [2] and RFC3110
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[6].
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3. RSA/SHA-256 RRSIG Resource Records
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RSA/SHA-256 signatures are stored in the DNS using RRSIG resource
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records (RRs) with algorithm number [TBA].
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The value of the signature field in the RRSIG RR is calculated as
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follows. The values for the fields that precede the signature data
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are specified in RFC4034 [2].
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hash = SHA-256(data)
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signature = ( 00 | 01 | FF* | 00 | prefix | hash ) ** e (mod n)
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Where SHA-256 is the message digest algorithm as specified in FIPS
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180 [5], | is concatenation, 00, 01, FF and 00 are fixed octets of
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corresponding hexadecimal value, "e" is the private exponent of the
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signing RSA key, and "n" is the public modulus of the signing key.
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The FF octet MUST be repeated the maximum number of times so that the
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total length of the signature equals the length of the modulus of the
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signer's public key ("n"). "data" is the data of the resource record
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set that is signed, as specified in RFC4034 [2].
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Jansen Expires July 5, 2006 [Page 3]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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The prefix is the ASN.1 BER SHA-256 algorithm designator prefix as
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specified in PKCS 2.1 [4]:
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hex 30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20
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This prefix should make the use of standard cryptographic libraries
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easier. These specifications are taken directly from PKCS #1 v2.1
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section 9.2 [4].
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4. Implementation Considerations
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DNSSEC aware implementations MUST be able to support RRSIG resource
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records with the RSA/SHA-256 algorithm.
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If both RSA/SHA-256 and RSA/SHA-1 RRSIG resource records are
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available for a certain rrset, with a secure path to their keys, the
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validator SHOULD ignore the SHA-1 signature. If the RSA/SHA-256
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signature does not verify the data, and the RSA/SHA-1 does, the
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validator SHOULD mark the data with the security status from the RSA/
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SHA-256 signature.
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5. IANA Considerations
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IANA has not yet assigned an algorithm number for RSA/SHA-256.
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The algorithm list from RFC4034 Appendix A.1 [2] is extended with the
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following entry:
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Zone
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Value Algorithm [Mnemonic] Signing References Status
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----- ----------- ----------- -------- ---------- ---------
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[tba] RSA/SHA-256 [RSASHA256] y [TBA] MANDATORY
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6. Security Considerations
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Recently, weaknesses have been discovered in the SHA-1 hashing
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algorithm. It is therefore strongly encouraged to deploy SHA-256
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where SHA-1 is used now, as soon as the DNS software supports it.
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SHA-256 is considered sufficiently strong for the immediate future,
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but predictions about future development in cryptography and
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cryptanalysis are beyond the scope of this document.
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Jansen Expires July 5, 2006 [Page 4]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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7. Acknowledgments
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This document is a minor extension to RFC4034 [2]. Also, we try to
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follow the documents RFC3110 [6] and draft-ietf-dnsext-ds-sha256.txt
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[8] for consistency. The authors of and contributors to these
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documents are gratefully acknowledged for their hard work.
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The following people provided additional feedback and text: Jaap
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Akkerhuis, Miek Gieben and Wouter Wijngaards.
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8. References
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8.1. Normative References
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[1] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
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"DNS Security Introduction and Requirements", RFC 4033,
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March 2005.
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[2] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
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"Resource Records for the DNS Security Extensions", RFC 4034,
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March 2005.
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[3] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
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"Protocol Modifications for the DNS Security Extensions",
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RFC 4035, March 2005.
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[4] Jonsson, J. and B. Kaliski, "Public-Key Cryptography Standards
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(PKCS) #1: RSA Cryptography Specifications Version 2.1",
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RFC 3447, February 2003.
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[5] National Institute of Standards and Technology, "Secure Hash
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Standard", FIPS PUB 180-2, August 2002.
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[6] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name
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System (DNS)", RFC 3110, May 2001.
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8.2. Informative References
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[7] Schneier, B., "Applied Cryptography Second Edition: protocols,
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algorithms, and source code in C", Wiley and Sons , ISBN 0-471-
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11709-9, 1996.
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[8] Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer (DS)
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Resource Records (RRs)", Work in Progress Feb 2006.
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Jansen Expires July 5, 2006 [Page 5]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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Author's Address
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Jelte Jansen
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NLnet Labs
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Kruislaan 419
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Amsterdam 1098VA
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NL
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Email: jelte@NLnetLabs.nl
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URI: http://www.nlnetlabs.nl/
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Jansen Expires July 5, 2006 [Page 6]
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Internet-Draft RSA/SHA-256 DNSKEYs and RRSIGS January 2006
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Intellectual Property Statement
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The IETF takes no position regarding the validity or scope of any
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Intellectual Property Rights or other rights that might be claimed to
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pertain to the implementation or use of the technology described in
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this document or the extent to which any license under such rights
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might or might not be available; nor does it represent that it has
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made any independent effort to identify any such rights. Information
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on the procedures with respect to rights in RFC documents can be
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found in BCP 78 and BCP 79.
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Copies of IPR disclosures made to the IETF Secretariat and any
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assurances of licenses to be made available, or the result of an
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attempt made to obtain a general license or permission for the use of
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such proprietary rights by implementers or users of this
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specification can be obtained from the IETF on-line IPR repository at
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http://www.ietf.org/ipr.
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The IETF invites any interested party to bring to its attention any
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copyrights, patents or patent applications, or other proprietary
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rights that may cover technology that may be required to implement
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this standard. Please address the information to the IETF at
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ietf-ipr@ietf.org.
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Disclaimer of Validity
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This document and the information contained herein are provided on an
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"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
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OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
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INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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Copyright Statement
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Copyright (C) The Internet Society (2006). This document is subject
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to the rights, licenses and restrictions contained in BCP 78, and
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except as set forth therein, the authors retain all their rights.
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Acknowledgment
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Funding for the RFC Editor function is currently provided by the
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Internet Society.
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Jansen Expires July 5, 2006 [Page 7]
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