This package is based on the package 'libzrtpcpp' from project 'openSUSE:Factory'.

This library is a GPL licensed extension to the GNU RTP Stack, ccrtp,
that offers compatibility with Phil Zimmermann's zrtp/Zfone voice
encryption, and which can be directly embedded into telephony
applications.

https://www.acritelli.com/hacking-voip-decrypting-sdes-protected-srtp-phone-calls/
TLS support is mandatory for use of SRTP, but ZRTP should be used instead of SRTP