Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms
RFC 6151

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>
Subject: Document Action: 'Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms' to Informational RFC (draft-turner-md5-seccon-update-08.txt)

The IESG has approved the following document:
- 'Updated Security Considerations for the MD5 Message-Digest and the
   HMAC-MD5 Algorithms'
  (draft-turner-md5-seccon-update-08.txt) as an Informational RFC

This document has been reviewed in the IETF but is not the product of an
IETF Working Group.

The IESG contact person is Alexey Melnikov.

A URL of this Internet Draft is:
http://datatracker.ietf.org/doc/draft-turner-md5-seccon-update/

Technical Summary

   This document updates the security considerations for MD5 and HMAC-MD5.

Working Group Summary

   The authors asked for comments from the saag and cfrg mailing lists.
   All of the comments were received off list. The reviewers are noted in the
   acknowledgments section.

Document Quality

   Prominent reviewers are noted in the draft's acknowledgment section.

RFC Editor Note

Please replace Section 2 to read:

   MD5 was published in 1992 as an Informational RFC.  Since that time,
   MD5 has been extensively studied and new cryptographic attacks have
   been discovered.  Message digest algorithms are designed to provide
   collision, pre-image, and second pre-image resistance.  In addition,
   message digest algorithms are used with a shared secret value for
   message authentication in HMAC, and in this context, some people may
   find the guidance for key lengths and algorithm strengths in
   [SP800-57] and [SP800-131] useful.

   MD5 is no longer acceptable where collision resistance is required
   such as digital signatures.  It is not urgent to stop using MD5 in
   other ways, such as HMAC-MD5; however, since MD5 must not be used for
   digital signatures, new protocol designs should not employ HMAC-MD5.
   Alternatives to HMAC-MD5 include HMAC-SHA256 [HMAC][HMAC-SHA256] and
   [AES-CMAC] when AES is more readily available than a hash function.