Extended Key Usage (EKU) for Session Initiation Protocol (SIP) X.509 Certificates
RFC 5924

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Internet Engineering Task Force (IETF)                       S. Lawrence
Request for Comments: 5924
Category: Experimental                                        V. Gurbani
ISSN: 2070-1721                        Bell Laboratories, Alcatel-Lucent
                                                               June 2010

     Extended Key Usage (EKU) for Session Initiation Protocol (SIP)
                           X.509 Certificates

Abstract

   This memo documents an extended key usage (EKU) X.509 certificate
   extension for restricting the applicability of a certificate to use
   with a Session Initiation Protocol (SIP) service.  As such, in
   addition to providing rules for SIP implementations, this memo also
   provides guidance to issuers of certificates for use with SIP.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  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/rfc5924.

Lawrence & Gurbani            Experimental                      [Page 1]
RFC 5924                         SIP EKU                       June 2010

Copyright Notice

   Copyright (c) 2010 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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   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................3
      2.1. Key Words ..................................................3
      2.2. Abstract Syntax Notation ...................................3
   3. Problem Statement ...............................................3
   4. Restricting Usage to SIP ........................................4
      4.1. Extended Key Usage Values for SIP Domains ..................5
   5. Using the SIP EKU in a Certificate ..............................5
   6. Implications for a Certification Authority ......................6
   7. Security Considerations .........................................6
   8. IANA Considerations .............................................6
   9. Acknowledgments .................................................7
   10. Normative References ...........................................7
   Appendix A.  ASN.1 Module ..........................................8

Lawrence & Gurbani            Experimental                      [Page 2]
RFC 5924                         SIP EKU                       June 2010

1.  Introduction

   This memo documents an extended key usage (EKU) X.509 certificate
   extension for restricting the applicability of a certificate to use
   with a Session Initiation Protocol (SIP) service.  As such, in
   addition to providing rules for SIP implementations, this memo also
   provides guidance to issuers of certificates for use with SIP.

2.  Terminology

2.1.  Key Words

   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 [1].

   Additionally, the following term is defined: