PJSIP now has SRTP support in SVN trunk (hurray!). For more information about compatibility, how to use, and what have been done, please see the SRTP wiki in
We’ve tested it against couple of phones that support SRTP and it looks good (apart from SRTCP, which one phone doesn’t support and the other we don’t think it implements SRTCP correctly). If you have phones which support SRTP, it would be great if you could give it a try, I’ll be thrilled to hear your result.
Enjoy it while it’s hot!