Date Added: Aug 2011
This paper specifies a two-step migration towards a stronger authentication in the Session Initiation Protocol. First, the authors add support for a Password Authenticated Key Exchange algorithm that can function as a drop-in replacement for the widely adopted Digest Access Authentication mechanism. This new authentication mechanism adds support for mutual authentication, is considered stronger and can rely on the same shared password used by the digest authentication. A more long-term solution is to replace the authentication scheme with the Simple Authentication and Security Layer. The Simple Authentication and Security Layer separates the authentication mechanisms from the Session Initiation Protocol, and adds support for a range of more secure authentication mechanisms in a generic and unified way.