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Key Management Considerations for the TCP MD5 Signature Option (RFC3562)

IP.com Disclosure Number: IPCOM000016607D
Original Publication Date: 2003-Jul-01
Included in the Prior Art Database: 2003-Jul-03
Document File: 8 page(s) / 15K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Leech: AUTHOR

Abstract

The TCP MD5 Signature Option (RFC 2385), used predominantly by BGP, has seen significant deployment in critical areas of Internet infrastructure. The security of this option relies heavily on the quality of the keying material used to compute the MD5 signature. This document addresses the security requirements of that keying material.

This text was extracted from an ASCII text file.
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Network Working Group� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � M. Leech

Request for Comments: 3562� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � Nortel Networks

Category:Informational� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � July 2003

� � � � � � � � � � � � � � � � � � Key Management Considerations for

� � � � � � � � � � � � � � � � � � � � the TCP MD5 Signature Option

Status of this Memo

� � This memo provides information for the Internet community.� It does

� � not specify an Internet standard of any kind.� Distribution of this

� � memo is unlimited.

Copyright Notice

� � Copyright (C) The Internet Society (2003).� All Rights Reserved.

Abstract

� � The TCP MD5 Signature Option (RFC 2385), used predominantly by BGP,

� � has seen significant deployment in critical areas of Internet

� � infrastructure.� The security of this option relies heavily on the

� � quality of the keying material used to compute the MD5 signature.

� � This document addresses the security requirements of that keying

� � material.

1. Introduction

� � The security of various cryptographic functions lies both in the

� � strength of the functions themselves against various forms of attack,

� � and also, perhaps more importantly, in the keying material that is

� � used with them.� While theoretical attacks against the simple MAC

� � construction used in RFC 2385 are possible [MDXMAC], the number of

� � text-MAC pairs required to mount a forgery make it vastly more

� � probable that key-guessing is the main threat against RFC 2385.

� � We show a quantitative approach to determining the security

� � requirements of keys used with [RFC2385], which tends to suggest the

� � following:

� � � � � o� Key lengths SHOULD be between 12 and 24 bytes, with larger keys

� � � � � � � � having effectively zero additional computational costs when

� � � � � � � � compared to shorter keys.

Leech� � � � � � � � � � � � � � � � � � � � � � � Informational� � � � � � � � � � � � � � � � � � � � � [Page 1]

RFC 3562� � � Considerations for the TCP MD5 Signature Option� � � July 2003

� � � � � o� Key sharing SHOULD be limited so that keys aren't shared among

� � � � � � � � multiple BGP peering arrangements.

� � � � � o� Keys SHOULD be changed at least every 90 days.

1.1. Requirements Keywords

� � The keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",

� � and "MAY" that appear in this document are to be interpreted as

� � described in [RFC2119].

2. Performance assumptions

� � The most recent performance study of MD5 that this author was able to

� � find was undertaken by J. Touch at ISI.� The results of this study

� � were documented in [RFC1810].� The assumption is that Moores Law

� � applies to the data in the study, which at the time showed a

� � best-possible *software* performance for MD5 of 87Mbits/second.

� � Projecting this number forward to the ca 2002 timeframe of this

� � document, w...