Update to the Cryptographic Message Syntax (CMS) for Algorithm Identifier Protection
draft-housley-lamps-cms-update-alg-id-protect-00

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Network Working Group                                         R. Housley
Internet-Draft                                            Vigil Security
Updates: 5652 (if approved)                             October 03, 2019
Intended status: Standards Track
Expires: April 5, 2020

     Update to the Cryptographic Message Syntax (CMS) for Algorithm
                         Identifier Protection
            draft-housley-lamps-cms-update-alg-id-protect-00

Abstract

   This document updates the Cryptographic Message Syntax (CMS)
   specified in RFC 5652 to ensure that algorithm identifiers are
   adequately protected.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on April 5, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Require use the same hash algorithm . . . . . . . . . . . . .   3
     3.1.  RFC 5652, Section 5.3 . . . . . . . . . . . . . . . . . .   3
     3.2.  RFC 5652, Section 5.4 . . . . . . . . . . . . . . . . . .   4
     3.3.  RFC 5652, Section 5.6 . . . . . . . . . . . . . . . . . .   4
     3.4.  Backward Compatibility Considerations . . . . . . . . . .   5
     3.5.  Timestamp Compatibility Considerations  . . . . . . . . .   5
   4.  Recommend inclusion of the CMSAlgorithmProtection attribute .   5
     4.1.  RFC 5652, Section 14  . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This document updates the Cryptographic Message Syntax (CMS)
   [RFC5652] to ensure that algorithm identifiers are adequately
   protected.

   The CMS Signed-data Content Type [RFC5652], unlike X.509 certificates
   [RFC5280], can be vulnerable to algorithm substitution attacks.  In
   an algorithm substitution attack, the attacker changes either the
   algorithm identifier or the parameters associated with the algorithm
   identifier to change the verification process used by the recipient.
   The X.509 certificate structure protects the algorithm identifier and
   the associate parameters by signing them.

   In an algorithm substitution attack, the attacker looks for a
   different algorithm that produces the same result as the algorithm
   used by the originator.  As an example, if the signer of a message
   used SHA-256 [SHS] as the digest algorithm to hash the message
   content, then the attacker looks for a weaker hash algorithm that
   produces a result that is of the same length.  The attacker's goal is
   to find a different message that results in the same hash value,
   which is commonly called a collision.  Today, there are many hash
   functions that produce 256-bit results.  One of them may be found to
   be weak in the future.

   Further, when a digest algorithm produces a larger result than is
   needed by a digital signature algorithm, the digest value is reduced
   to the size needed by the signature algorithm.  This can be done both

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