MD4 to Historic Status
RFC 6150

Document Type RFC - Informational (March 2011; Errata)
Obsoletes RFC 1320
Was draft-turner-md4-to-historic (individual in gen area)
Authors Lily Chen  , Sean Turner 
Last updated 2020-01-21
Stream Internent Engineering Task Force (IETF)
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IESG IESG state RFC 6150 (Informational)
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Responsible AD Robert Sparks
Send notices to (None)
Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 6150                                          IECA
Obsoletes: 1320                                                  L. Chen
Category: Informational                                             NIST
ISSN: 2070-1721                                               March 2011

                         MD4 to Historic Status


   This document retires RFC 1320, which documents the MD4 algorithm,
   and discusses the reasons for doing so.  This document moves RFC 1320
   to Historic status.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Turner & Chen                 Informational                     [Page 1]
RFC 6150                 MD2 to Historic Status               March 2011

1.  Introduction

   MD4 [MD4] is a message digest algorithm that takes as input a message
   of arbitrary length and produces as output a 128-bit "fingerprint" or
   "message digest" of the input.  This document retires [MD4].
   Specifically, this document moves RFC 1320 [MD4] to Historic status.
   The reasons for taking this action are discussed.

   [HASH-Attack] summarizes the use of hashes in many protocols and
   discusses how attacks against a message digest algorithm's one-way
   and collision-free properties affect and do not affect Internet
   protocols.  Familiarity with [HASH-Attack] is assumed.

2.  Rationale

   MD4 was published in 1992 as an Informational RFC.  Since its
   publication, MD4 has been under attack [denBORBOS1992] [DOBB1995]
   [DOBB1996] [GLRW2010] [WLDCY2005] [LUER2008].  In fact, RSA, in 1996,
   suggested that MD4 should not be used [RSA-AdviceOnMD4].  Microsoft
   also made similar statements [MS-AdviceOnMD4].

   In Section 6, this document discusses attacks against MD4 that
   indicate use of MD4 is no longer appropriate when collision
   resistance is required.  Section 6 also discusses attacks against
   MD4's pre-image and second pre-image resistance.  Additionally,
   attacks against MD4 used in message authentication with a shared
   secret (i.e., HMAC-MD4) are discussed.

3.  Documents that Reference RFC 1320

   Use of MD4 has been specified in the following RFCs:

   Internet Standard (IS):

     o [RFC2289] A One-Time Password System.

   Draft Standard (DS):

     o [RFC1629] Guidelines for OSI NSAP Allocation in the Internet.

   Proposed Standard (PS):

     o [RFC3961] Encryption and Checksum Specifications for Kerberos 5.

   Best Current Practice (BCP):

     o [RFC4086] Randomness Requirements for Security.

Turner & Chen                 Informational                     [Page 2]
RFC 6150                 MD2 to Historic Status               March 2011


     o [RFC1760] The S/KEY One-Time Password System.

     o [RFC1983] Internet Users' Glossary.

     o [RFC2433] Microsoft PPP CHAP Extensions.

     o [RFC2759] Microsoft PPP CHAP Extensions, Version 2.

     o [RFC3174] US Secure Hash Algorithm 1 (SHA1).

     o [RFC4757] The RC4-HMAC Kerberos Encryption Types Used by
                 Microsoft Windows.

     o [RFC5126] CMS Advanced Electronic Signatures (CAdES).

   There are other RFCs that refer to MD2, but they have been either
   moved to Historic status or obsoleted by a later RFC.  References and
   discussions about these RFCs are omitted.  The notable exceptions

     o [RFC2313] PKCS #1: RSA Encryption Version 1.5.

     o [RFC2437] PKCS #1: RSA Cryptography Specifications Version 2.0.

     o [RFC3447] Public-Key Cryptography Standards (PKCS) #1: RSA
               Cryptography Specifications Version 2.1.

4.  Impact of Moving MD4 to Historic
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