A secure SIP VoIP client using the new security features from RFC3261 like S/MIME. A console application written in c++.
Have a look at our sf.net project page
This project was original developed as a diploma thesis at Zurich University of Applied Sciences Winterthur (ZHW) (english).
In a earlier term project we took a look at possible security features applicable for SIP infrastructures. We found clients with TLS and HTTP authentication, but none with support for S/MIME. For the media channel there is no security protocol avaiable. Except SRTP - a draft (and eventually a standard in 2005). The paper is avaiable here in German.
So we introduced our diploma thesis: A proof of concept for a full encrypted SIP communication using S/MIME for SIP and SRTP for media channel. In seven weeks we developped a client that is able to establish a connection like that. We wrote about then thousand lines of code and a hundred and fifty page documentation. (Documentation soon avaiable in German)
Finally we will provide our experience to the public. The client is released under the GNU Public Licence to enable developpers of other SIP clients to enhance their clients with security.
 Daniel Kaufmann, Andreas Stricker
 Andreas Gisler, Loretz Manfred, Andreas Stricker