Example Call Flows Using Session Initiation Protocol (SIP) Security Mechanisms
RFC 6216

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Internet Engineering Task Force (IETF)                       C. Jennings
Request for Comments: 6216                                 Cisco Systems
Category: Informational                                           K. Ono
ISSN: 2070-1721                                      Columbia University
                                                               R. Sparks
                                                         B. Hibbard, Ed.
                                                                 Tekelec
                                                              April 2011

       Example Call Flows Using Session Initiation Protocol (SIP)
                          Security Mechanisms

Abstract

   This document shows example call flows demonstrating the use of
   Transport Layer Security (TLS), and Secure/Multipurpose Internet Mail
   Extensions (S/MIME) in Session Initiation Protocol (SIP).  It also
   provides information that helps implementers build interoperable SIP
   software.  To help facilitate interoperability testing, it includes
   certificates used in the example call flows and processes to create
   certificates for testing.

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
   http://www.rfc-editor.org/info/rfc6216.

Jennings, et al.              Informational                     [Page 1]
RFC 6216                  SIP Secure Call Flows               April 2011

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
   (http://trustee.ietf.org/license-info) 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.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Certificates . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  CA Certificates  . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Host Certificates  . . . . . . . . . . . . . . . . . . . .  8
     2.3.  User Certificates  . . . . . . . . . . . . . . . . . . . . 10
   3.  Call Flow with Message Over TLS  . . . . . . . . . . . . . . . 12
     3.1.  TLS with Server Authentication . . . . . . . . . . . . . . 12
     3.2.  MESSAGE Transaction Over TLS . . . . . . . . . . . . . . . 13
   4.  Call Flow with S/MIME-Secured Message  . . . . . . . . . . . . 15
     4.1.  MESSAGE Request with Signed Body . . . . . . . . . . . . . 15
     4.2.  MESSAGE Request with Encrypted Body  . . . . . . . . . . . 20
     4.3.  MESSAGE Request with Encrypted and Signed Body . . . . . . 22
   5.  Observed Interoperability Issues . . . . . . . . . . . . . . . 27
   6.  Additional Test Scenarios  . . . . . . . . . . . . . . . . . . 29
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 31
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 32
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 32
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 32
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 34
   Appendix A.  Making Test Certificates  . . . . . . . . . . . . . . 35
     A.1.  makeCA script  . . . . . . . . . . . . . . . . . . . . . . 36
     A.2.  makeCert script  . . . . . . . . . . . . . . . . . . . . . 40
   Appendix B.  Certificates for Testing  . . . . . . . . . . . . . . 42
     B.1.  Certificates Using EKU . . . . . . . . . . . . . . . . . . 42
     B.2.  Certificates NOT Using EKU . . . . . . . . . . . . . . . . 51
     B.3.  Certificate Chaining with a Non-Root CA  . . . . . . . . . 58
   Appendix C.  Message Dumps . . . . . . . . . . . . . . . . . . . . 64

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1.  Introduction

   This document is informational and is not normative on any aspect of
   SIP.

   SIP with TLS ([RFC5246]) implementations are becoming very common.