--- 1/draft-ietf-dnsext-rfc2539bis-dhk-04.txt 2006-02-04 23:12:29.000000000 +0100 +++ 2/draft-ietf-dnsext-rfc2539bis-dhk-05.txt 2006-02-04 23:12:29.000000000 +0100 @@ -1,19 +1,19 @@ INTERNET-DRAFT Diffie-Hellman Information in the DNS OBSOLETES: RFC 2539 Donald E. Eastlake 3rd Motorola Laboratories -Expires: February 2005 August 2004 +Expires: September 2005 March 2005 Storage of Diffie-Hellman Keying Information in the DNS ------- -- -------------- ------ ----------- -- --- --- - + Status of This Document By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. Distribution of this document is unlimited. Comments should be sent to the DNS extensions working group mailing list @@ -35,21 +35,21 @@ The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract The standard method for encoding Diffie-Hellman keys in the Domain Name System is specified. Copyright - Copyright (C) The Internet Society 2004. + Copyright (C) The Internet Society 2005. INTERNET-DRAFT Diffie-Hellman Information in the DNS Acknowledgements Part of the format for Diffie-Hellman keys and the description thereof was taken from a work in progress by Ashar Aziz, Tom Markson, and Hemma Prafullchandra. In addition, the following persons provided useful comments that were incorporated into the predecessor of this document: Ran Atkinson, Thomas Narten. @@ -134,42 +134,42 @@ INTERNET-DRAFT Diffie-Hellman Information in the DNS in deciding on a p and g, see [RFC 2631]. 2. Encoding Diffie-Hellman Keying Information When Diffie-Hellman keys appear within the RDATA portion of a RR, they are encoded as shown below. The period of key validity is not included in this data but is - indicated separately, for example by an RR which signs and - authenticates the RR containing the keying information. + indicated separately, for example by an RR such as RRSIG which signs + and authenticates the RR containing the keying information. 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | KEY flags | protocol | algorithm=2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | prime length (or flag) | prime (p) (or special) / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / prime (p) (variable length) | generator length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | generator (g) (variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | public value length | public value (variable length)/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / public value (g^i mod p) (variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Prime length is length of the Diffie-Hellman prime (p) in bytes if it - is 16 or greater. Prime contains the binary representation of the - Diffie-Hellman prime with most significant byte first (i.e., in + Prime length is the length of the Diffie-Hellman prime (p) in bytes + if it is 16 or greater. Prime contains the binary representation of + the Diffie-Hellman prime with most significant byte first (i.e., in network order). If "prime length" field is 1 or 2, then the "prime" field is actually an unsigned index into a table of 65,536 prime/generator pairs and the generator length SHOULD be zero. See Appedix A for defined table entries and Section 4 for information on allocating additional table entries. The meaning of a zero or 3 through 15 value for "prime length" is reserved. Generator length is the length of the generator (g) in bytes. Generator is the binary representation of generator with most significant byte first. PublicValueLen is the Length of the Public @@ -177,56 +177,57 @@ representation of the DH public value with most significant byte first. INTERNET-DRAFT Diffie-Hellman Information in the DNS 3. Performance Considerations Current DNS implementations are optimized for small transfers, typically less than 512 bytes including DNS overhead. Larger transfers will perform correctly and extensions have been - standardized [RFC 2671] to make larger transfers more efficient, it - is still advisable at this time to make reasonable efforts to + standardized [RFC 2671] to make larger transfers more efficient. But + it is still advisable at this time to make reasonable efforts to minimize the size of RR sets containing keying information consistent with adequate security. 4. IANA Considerations Assignment of meaning to Prime Lengths of 0 and 3 through 15 requires an IETF consensus as defined in [RFC 2434]. Well known prime/generator pairs number 0x0000 through 0x07FF can only be assigned by an IETF standards action. [RFC 2539], the Proposed Standard predecessor of this document, assigned 0x0001 - through 0x0002. This document assigns 0x0003. Pairs number 0s0800 - through 0xBFFF can be assigned based on RFC documentation. Pairs - number 0xC000 through 0xFFFF are available for private use and are - not centrally coordinated. Use of such private pairs outside of a - closed environment may result in conflicts and/or security failures. + through 0x0002. This document additionally assigns 0x0003. Pairs + number 0s0800 through 0xBFFF can be assigned based on RFC + documentation. Pairs number 0xC000 through 0xFFFF are available for + private use and are not centrally coordinated. Use of such private + pairs outside of a closed environment may result in conflicts and/or + security failures. 5. Security Considerations Keying information retrieved from the DNS should not be trusted unless (1) it has been securely obtained from a secure resolver or independently verified by the user and (2) this secure resolver and secure obtainment or independent verification conform to security policies acceptable to the user. As with all cryptographic algorithms, evaluating the necessary strength of the key is important and dependent on security policy. In addition, the usual Diffie-Hellman key strength considerations apply. (p-1)/2 should also be prime, g should be primitive mod p, p - should be "large", etc. [RFC 2631, Schneier] + should be "large", etc. See [RFC 2631, Schneier]. Copyright and Disclaimer - Copyright (C) The Internet Society 2004. This document is subject to + Copyright (C) The Internet Society 2005. This document is subject to the rights, licenses and restrictions contained in BCP 78 and except as set forth therein, the authors retain all their rights. INTERNET-DRAFT Diffie-Hellman Information in the DNS This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE @@ -273,39 +274,39 @@ Algorithms, and Source Code in C" (Second Edition), 1996, John Wiley and Sons. Author Address Donald E. Eastlake 3rd Motorola Laboratories 155 Beaver Street Milford, MA 01757 USA - Telephone: +1-508-786-7554 (w) + Telephone: +1-508-786-7554 INTERNET-DRAFT Diffie-Hellman Information in the DNS - +1-508-634-2066 (h) EMail: Donald.Eastlake@motorola.com Expiration and File Name - This draft expires in February 2005. + This draft expires in September 2005. - Its file name is draft-ietf-dnsext-rfc2539bis-dhk-04.txt. + Its file name is draft-ietf-dnsext-rfc2539bis-dhk-05.txt. INTERNET-DRAFT Diffie-Hellman Information in the DNS Appendix A: Well known prime/generator pairs These numbers are copied from the IPSEC effort where the derivation of - these values is more fully explained and additional information is available. + these values is more fully explained and additional information is + available. Richard Schroeppel performed all the mathematical and computational work for this appendix. A.1. Well-Known Group 1: A 768 bit prime The prime is 2^768 - 2^704 - 1 + 2^64 * { [2^638 pi] + 149686 }. Its decimal value is 155251809230070893513091813125848175563133404943451431320235 119490296623994910210725866945387659164244291000768028886422 915080371891804634263272761303128298374438082089019628850917