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Versions: 00 01 02 03 04 05 06 draft-ietf-uta-xmpp

Network Working Group                                     P. Saint-Andre
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Informational                         September 9, 2013
Expires: March 13, 2014


 Use of Transport Layer Security (TLS) in the Extensible Messaging and
                        Presence Protocol (XMPP)
                      draft-saintandre-xmpp-tls-00

Abstract

   This document provides recommendations for the use of Transport Layer
   Security (TLS) in the Extensible Messaging and Presence Protocol
   (XMPP).  This document updates RFC 6120.

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
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   Drafts is at http://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 March 13, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Discussion Venue  . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Recommendations . . . . . . . . . . . . . . . . . . . . . . . . 3
     4.1.  Protocol Versions . . . . . . . . . . . . . . . . . . . . . 3
     4.2.  Ciphersuites  . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 4
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 5




































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1.  Introduction

   The Extensible Messaging and Presence Protocol (XMPP) [RFC6120]
   (along with its precursor, the so-called "Jabber protocol") has used
   Transport Layer Security (TLS) [RFC5246] (along with its precursor,
   Secure Sockets Layer or SSL) since 1999.  Both [RFC6120] and its
   predecessor [RFC3920] provided recommendations regarding the use of
   TLS in XMPP.  Given the evolving threat model on the Internet today
   (see, for example, [I-D.trammell-perpass-ppa]), it is necessary to
   provide stronger recommendations (see also [I-D.sheffer-tls-bcp]).
   This document updates [RFC6120].


2.  Terminology

   Various security-related terms are to be understood in the sense
   defined in [RFC4949].

   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
   [RFC2119].


3.  Discussion Venue

   The discussion venue for this document is the mailing list of the
   XMPP Working Group, for which archives and subscription information
   can be found at <https://www.ietf.org/mailman/listinfo/xmpp>.


4.  Recommendations

4.1.  Protocol Versions

   XMPP implementations MUST NOT negotiate SSL version 2 [RFC6176].

   XMPP implementations MUST NOT negotiate SSL version 3.

   XMPP implementations MUST support, and prefer to negotiate, TLS
   version 1.2 [RFC5246].

   XMPP implementations MAY negotiate TLS version 1.1 [RFC4346].

   XMPP implementations MAY negotiate TLS version 1.0 [RFC2246].






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4.2.  Ciphersuites

   XMPP implementations MUST NOT negotiate RC4 ciphersuites
   [I-D.popov-tls-prohibiting-rc4].

   XMPP implementations MUST NOT negotiate ciphersuites that use so-
   called "export-level" encryption (including 40-bit and 56-bit
   algorithms).

   XMPP implementations MUST NOT negotiate ciphersuites that use less
   than 128-bit algorithms.

   XMPP implementations SHOULD prefer ciphersuites that use 256-bit
   algorithms or higher.

   XMPP implementations MUST support, and SHOULD prefer to negotiate,
   ciphersuites that offer perfect forward secrecy, such as those in the
   "EDH", "DHE", and "ECDH" families.


5.  Open Issues

   This document has the following open issues:

   o  Add information about the rationale for each recommendation,
      perhaps in an appendix.
   o  Recommend a specific ciphersuite or a small number of
      ciphersuites?
   o  Provide recommendations regarding key lengths?
   o  Discuss TLS compression vs. application-layer compression?


6.  IANA Considerations

   This document requests no actions of the IANA.


7.  Security Considerations

   This entire document discusses security.


8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.



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   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
              RFC 4949, August 2007.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC6120]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Core", RFC 6120, March 2011.

   [RFC6176]  Turner, S. and T. Polk, "Prohibiting Secure Sockets Layer
              (SSL) Version 2.0", RFC 6176, March 2011.

8.2.  Informative References

   [I-D.popov-tls-prohibiting-rc4]
              Popov, A., "Prohibiting RC4 Cipher Suites",
              draft-popov-tls-prohibiting-rc4-00 (work in progress),
              August 2013.

   [I-D.sheffer-tls-bcp]
              Sheffer, Y., "Recommendations for Secure Use of TLS and
              DTLS", draft-sheffer-tls-bcp-00 (work in progress),
              September 2013.

   [I-D.trammell-perpass-ppa]
              Trammell, B., "The Perfect Passive Adversary: A Threat
              Model for the Evaluation of Protocols under Pervasive
              Surveillance", draft-trammell-perpass-ppa-00 (work in
              progress), September 2013.

   [RFC2246]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
              RFC 2246, January 1999.

   [RFC3920]  Saint-Andre, P., Ed., "Extensible Messaging and Presence
              Protocol (XMPP): Core", RFC 3920, October 2004.

   [RFC4346]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.1", RFC 4346, April 2006.













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Author's Address

   Peter Saint-Andre
   Cisco Systems, Inc.
   1899 Wynkoop Street, Suite 600
   Denver, CO  80202
   USA

   Phone: +1-303-308-3282
   Email: psaintan@cisco.com









































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