This package provides a library that adds ZRTP support to the GNU ccRTP stack. Phil Zimmermann developed ZRTP to allow ad-hoc, easy to use key negotiation to setup Secure RTP (SRTP) sessions. GNU ZRTP together with GNU ccRTP (1.5.0 or later) provides a ZRTP implementation that can be directly embedded into client and server applications. The GNU ZRTP implementation is compliant to the basic functions of ZRTP as described in ''draft-zimmermann-avt-zrtp-08x''. Currently GNU ZRTP supports the basic features and multi-stream mode , not the enhanced features like PBX SAS relay or preshared mode. The GNU ZRTP implementation already defines the necessary external interfaces and functions for these enhanced features but they are not yet implemented (stubs only). You may access the ZRTP specification at this URL: [http://zfoneproject.com/zrtp_ietf.html] The first application to demonstrate this capability was the 0.8.2 release of the Twinkle softphone client. All following versions of Twinkle support GNU ZRTP as well. Please note, this library is licensed under the GNU GPL, version 3 or later, and has been copyright assigned to the Free Software Foundation. For further information refer to the ZRTP FAQ and the GNU ZRTP How-To. Both are part of the GNU Telephony wiki and are located in its documentation category. Here are the URLs: http://www.gnutelephony.org/index.php/GNU_ZRTP_How_To http://www.gnutelephony.org/index.php/ZRTP_FAQ