Network Working Group                                 J. Preuss Mattsson
Internet-Draft                                                  Ericsson
Intended status: Standards Track                       November 18, 2020
Expires: May 22, 2021


        Key Exchange Without Forward Secrecy is Not Recommended
              draft-mattsson-tls-psk-ke-dont-dont-dont-00

Abstract

   Key exchange without forward secrecy enables passive monitoring
   [RFC7258].  Massive pervasive monitoring attacks relying on key
   exchange without forward secrecy has been reported
   [I-D.ietf-emu-aka-pfs].  If key exchange without Diffe-Hellan is
   used, compromise of the long-term authenticatation key enables a
   passive attacker to compromise past and future sessions.  All TLS 1.2
   cipher suites without forward secrecy has been marked as NOT
   RECOMMENDED [RFC8447], and static RSA has been forbidden in TLS 1.3
   [RFC8446]. psk_ke does not provide forward secrecy and is NOT
   RECOMMENDED.  This document sets the IANA registration of psk_ke to
   NOT RECOMMENDED.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 22, 2021.

Copyright Notice

   Copyright (c) 2020 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
   (https://trustee.ietf.org/license-info) in effect on the date of



Preuss Mattsson           Expires May 22, 2021                  [Page 1]

 
Internet-DraftKey Exchange Without Forward Secrecy is Not RNovember 2020


   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.

Table of Contents

   1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   2
   3.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   2
     3.1.  Normative References  . . . . . . . . . . . . . . . . . .   2
     3.2.  Informative References  . . . . . . . . . . . . . . . . .   3
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

.  IANA Considerations

   IANA is requested to update the PskKeyExchangeMode registry under the
   Transport Layer Security (TLS) Parameters heading.  For psk_ke the
   "Recommended" value has been set to "N".

.  References

3.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.








Preuss Mattsson           Expires May 22, 2021                  [Page 2]

 
Internet-DraftKey Exchange Without Forward Secrecy is Not RNovember 2020


3.2.  Informative References

   [I-D.ietf-emu-aka-pfs]
              Arkko, J., Norrman, K., and V. Torvinen, "Perfect-Forward
              Secrecy for the Extensible Authentication Protocol Method
              for Authentication and Key Agreement (EAP-AKA' PFS)",
              draft-ietf-emu-aka-pfs-05 (work in progress), October
              2020.

   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
              2014, <https://www.rfc-editor.org/info/rfc7258>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8447]  Salowey, J. and S. Turner, "IANA Registry Updates for TLS
              and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018,
              <https://www.rfc-editor.org/info/rfc8447>.

Acknowledgments

   The authors want to thank Ari Keraenen for their valuable comments
   and feedback.

Author's Address

   John Preuss Mattsson
   Ericsson

   Email: john.mattsson@ericsson.com



















Preuss Mattsson           Expires May 22, 2021                  [Page 3]