libzrtp: 
libzrtp: GNU ZRTP is a C++ implementation of Phil Zimmermann's ZRTP 
libzrtp: specification, and is available under the GPL license.
libzrtp: 
libzrtp: https://www.gnu.org/software/ccrtp/zrtp.html
libzrtp: https://github.com/wernerd/ZRTPCPP/
libzrtp: 
libzrtp: 
libzrtp: 
libzrtp: 

