The tar.gz you posted isn't license compatible.  We do have an exception for the real zrtp lib.  But we put off implementing it till the final draft comes out.  Right now you can use zrtp with freeswitch if you use zfoned on the linux system your talking to.

/b

On Jul 20, 2008, at 11:17 PM, Robert Clayton wrote:

Is anyone attempting to implement the ZRTP cryptographic key-agreement protocol (a method of encrypting voice data using self-generated keys, rather than keys from certificate authorities).
Some softphones such as X-Lite already implement it.
There is apparently an open source library at ftp://ftp.gnu.org/gnu/ccrtp/libzrtpcpp-0.9.0.tar.gz