Just came across the following blog post that thought could be of interest to those on this list...
Let's talk about ZRTP http://blog.cryptographyengineering.com/2012/11/lets-talk-about-zrtp.html .. [snipped]... The subject of today's post is the ZRTP key agreement protocol. ZRTP has recently gotten some press for being the primary key agreement used by Silent Circle, a new encrypted voice/video/text service launched by PGP inventor Phil Zimmermann and some other bright folks. But it's also used in other secure VoIP solutions, like Zfone and Moxie's RedPhone. .. [snipped]... -- Unsubscribe, change to digest, or change password at: https://mailman.stanford.edu/mailman/listinfo/liberationtech