Phil Zimmerman, the guy behind PGP, is working on a new product; Zfone . Zfone encrypts voice traffic on the fly and works with VoIP clients like X-Lite and Gizmo that use the SIP protocol. The software uses a simple voice authentication system so there is no need to agree on encryption keys in advance or to type in long passwords.
In the future, the ZRTP protocol will be integrated into standalone secure VoIP clients, but today we have a software product that lets you turn your existing VoIP client into a secure phone. The current Zfone software runs in the Internet Protocol stack on any Windows XP, Mac OS X, or Linux PC, and intercepts and filters all the VoIP ...