Storage of Diffie-Hellman Keys in the Domain Name System (DNS)
RFC 2539
| Document | Type |
RFC - Proposed Standard
(March 1999; No errata)
Updated by RFC 6944
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 2539 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group D. Eastlake
Request for Comments: 2539 IBM
Category: Standards Track March 1999
Storage of Diffie-Hellman Keys in the Domain Name System (DNS)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
A standard method for storing Diffie-Hellman keys in the Domain Name
System is described which utilizes DNS KEY resource records.
Acknowledgements
Part of the format for Diffie-Hellman keys and the description
thereof was taken from a work in progress by:
Ashar Aziz <ashar.aziz@eng.sun.com>
Tom Markson <markson@incog.com>
Hemma Prafullchandra <hemma@eng.sun.com>
In addition, the following person provided useful comments that have
been incorporated:
Ran Atkinson <rja@inet.org>
Thomas Narten <narten@raleigh.ibm.com>
Eastlake Standards Track [Page 1]
RFC 2539 Diffie-Hellman Keys in the DNS March 1999
Table of Contents
Abstract...................................................1
Acknowledgements...........................................1
1. Introduction............................................2
1.1 About This Document....................................2
1.2 About Diffie-Hellman...................................2
2. Diffie-Hellman KEY Resource Records.....................3
3. Performance Considerations..............................4
4. IANA Considerations.....................................4
5. Security Considerations.................................4
References.................................................5
Author's Address...........................................5
Appendix A: Well known prime/generator pairs...............6
A.1. Well-Known Group 1: A 768 bit prime..................6
A.2. Well-Known Group 2: A 1024 bit prime.................6
Full Copyright Notice......................................7
1. Introduction
The Domain Name System (DNS) is the current global hierarchical
replicated distributed database system for Internet addressing, mail
proxy, and similar information. The DNS has been extended to include
digital signatures and cryptographic keys as described in [RFC 2535].
Thus the DNS can now be used for secure key distribution.
1.1 About This Document
This document describes how to store Diffie-Hellman keys in the DNS.
Familiarity with the Diffie-Hellman key exchange algorithm is assumed
[Schneier].
1.2 About Diffie-Hellman
Diffie-Hellman requires two parties to interact to derive keying
information which can then be used for authentication. Since DNS SIG
RRs are primarily used as stored authenticators of zone information
for many different resolvers, no Diffie-Hellman algorithm SIG RR is
defined. For example, assume that two parties have local secrets "i"
and "j". Assume they each respectively calculate X and Y as follows:
X = g**i ( mod p ) Y = g**j ( mod p )
They exchange these quantities and then each calculates a Z as
follows:
Zi = Y**i ( mod p ) Zj = X**j ( mod p )
Eastlake Standards Track [Page 2]
RFC 2539 Diffie-Hellman Keys in the DNS March 1999
shared secret between the two parties that an adversary who does not
know i or j will not be able to learn from the exchanged messages
(unless the adversary can derive i or j by performing a discrete
logarithm mod p which is hard for strong p and g).
The private key for each party is their secret i (or j). The public
key is the pair p and g, which must be the same for the parties, and
their individual X (or Y).
2. Diffie-Hellman KEY Resource Records
Diffie-Hellman keys are stored in the DNS as KEY RRs using algorithm
number 2. The structure of the RDATA portion of this RR is as shown
below. The first 4 octets, including the flags, protocol, and
algorithm fields are common to all KEY RRs as described in [RFC
2535]. The remainder, from prime length through public value is the
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