Deprecating MD5 and SHA1 in TLS 1.2
draft-lvelvindron-tls-md5-sha1-deprecate-01

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Document Type Active Internet-Draft (individual)
Authors Loganaden Velvindron  , Kathleen Moriarty 
Last updated 2019-05-08
Replaced by draft-ietf-tls-md5-sha1-deprecate
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Internet Engineering Task Force                            L. Velvindron
Internet-Draft                                             cyberstorm.mu
Updates: 5246 7525 (if approved)                             K. Moriarty
Intended status: Standards Track                                Dell EMC
Expires: November 8, 2019                                    May 7, 2019

                  Deprecating MD5 and SHA1 in TLS 1.2
              draft-lvelvindron-tls-md5-sha1-deprecate-01

Abstract

   The MD5 and SHA1 hashing algorithms are steadily weakening in
   strength and their deprecation process should begin for their use in
   the TLS 1.2.

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 November 8, 2019.

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   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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Signature Algorithms  . . . . . . . . . . . . . . . . . . . .   2
   3.  Certificate Requests  . . . . . . . . . . . . . . . . . . . .   3
   4.  Server Key Exchange . . . . . . . . . . . . . . . . . . . . .   3
   5.  Certificate Verify  . . . . . . . . . . . . . . . . . . . . .   3
   6.  Updates to RFC5246  . . . . . . . . . . . . . . . . . . . . .   3
   7.  Updates to RFC7525  . . . . . . . . . . . . . . . . . . . . .   3
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   9.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   4
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   4
     10.2.  Informative References . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The usage of MD5 and SHA1 for TLS 1.2 is specified RFC 5246
   [RFC5246].  MD5 and SHA-1 have been proven to be insecure, subject to
   collision attacks.  RFC 6151 [RFC6151] details the security
   considerations, including collision attacks for MD5, published in
   2011.  MD5 has been deprecated by NIST and is no longer mentioned in
   publications such as [NISTSP800-131A-R2].  NIST formally deprecated
   use of SHA-1 in 2011 [NISTSP800-131A-R2] and disallowed its use for
   digital signatures at the end of 2013, based on both the Wang, et.
   al, attack and the potential for brute-force attack.  Further, in
   2017, researchers from Google and CWI Amsterdam [SHA-1-Collision]
   proved SHA-1 collision attacks were practical.  This document updates
   RFC 5246 [RFC5246] and RFC7525 [RFC7525] in such as way that MD5 and
   SHA1 MUST NOT be used for cryptographic hash functions.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Signature Algorithms

   Clients SHOULD NOT include md5 and SHA-1 in signature_algorithms
   extension.  If a client does not send a signature_algorithms
   extension, then the server MUST abort the handshake and send a
   handshake_failure alert.

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3.  Certificate Requests

   Servers SHOULD NOT include md5 and SHA-1 in CertificateRequest
   message.

4.  Server Key Exchange

   Servers MUST NOT include md5 and SHA-1 in ServerKeyExchange message.
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