http://www.rfc-editor.org/rfc/rfc5922.txt
RFC 5922: Domain Certificates in the Session Initiation Protocol (SIP), V. Gurbani, S. Lawrence, A. Jeffrey2010-06-01T23:00:00-00:00This document describes how to construct and interpret certain information in a PKIX-compliant (Public Key Infrastructure using X.509) certificate for use in a Session Initiation Protocol (SIP) over Transport Layer Security (TLS) connection. More specifically, this document describes how to encode and extract the identity of a SIP domain in a certificate and how to use that identity for SIP domain authentication. As such, this document is relevant both to implementors of SIP and to issuers of certificates. [STANDARDS-TRACK]