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Attacks on Cryptographic Hashes in Internet Protocols

Document Type Expired Internet-Draft (individual)
Expired & archived
Authors Paul E. Hoffman , Bruce Schneier
Last updated 2013-11-04 (Latest revision 2013-04-29)
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date (None)
Responsible AD (None)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


Announcements in the past decade of better-than-expected collision attacks in popular hash algorithms have caused some people to question whether common Internet protocols need to be changed, and if so, how. This document summarizes the use of hashes in many protocols, discusses how the collision attacks affect and do not affect the protocols, shows how to thwart known attacks on digital certificates, and discusses future directions for protocol designers. It also gives rationales for moving away from some hash algorithms altogether and for choosing when to start using newer, presumably better, hash algorithms in Internet protocols. This document obsoletes RFC 4270 and introduces significant new material that has been learned since the publication of that document.


Paul E. Hoffman
Bruce Schneier

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)