GNU Telephony is happy to announce that with the latest release of the GNU RTP Stack, GNU ccrtp 1.5, we are introducing a free software framework for developing both the secure RTP profile for VOIP (as defined by RFC 3711), and also a GNU GPL licensed implementation of Phil Zimmermann's ZRTP protocol for voice encryption as used in "Zfone". By offering a native secure RTP framework that can be directly embedded in newly developed VOIP applications, GNU Telephony intends to promote the development and widespread use of secure and intercept free voice and video communication services worldwide.
The Twinkle softphone package, starting with release 0.9, is the first complete free software package to make use of Secure call features offered in the GNU RTP Stack and may well be the first stand-alone zrtp compatible VOIP client available anywhere.
The GNU RTP stack can be used to develop secure communications for GNU/Linux hosted applications. The stack may also be used to develop application on various BSD systems including Mac OS/X, on Microsoft Windows, and even for embedded systems. We have tested and built the GNU RTP Stack with Handhelds Open Embedded build environment, and we look forward to implementing a Twinkle based secure calling solutions on Linux kernel powered cell phones in the future.
Securing RTP sessions is part of our vision in GNU Telephony for making passive voice communication intercept a thing of the past. By making "secure by design" encryption capabilities simple to embed, and by enabling the largest possible participation in developing such solutions through free software, we hope to break down those remaining barriers that prevent secure telephony from being widely deployed over next generation telephone networks. Part of this vision includes offering TLS encapsulated SIP over TCP, and deployment of anonymous calling proxies, to deny passive data mining of call session and connection
associative information in the future.
Phil Zimmerman's zrtp specification; http://www.infosecwriters.com/text_resources/pdf/Zfone_SSotillo.pdf.
Zfone project; http://www.philzimmermann.com/zfoneproject/index.html.
GNU Telephony Secure Calling; http://wiki.gnutelephony.org/index.php/Secure_Call.
Twinkle Softphone; http://www.twinklephone.com/.
Open Embedded; http://www.handhelds.org/geeklog/index.php.