Variations on https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Protocol https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Pro... - mainly used as

Variations on https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Protocol https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Pro... - mainly used as ZRTP, or DTLS+SRTP, or SRTP with manual key setup. Related: port knocking utils use encrypted/authenticated UDP datagrams; there are secure chat / instant messenger libraries using UDP; VoIP uses secure UDP. a minimalist approach is http://www.the-control-freak.com/ClntSrvr/AES/AES.htm http://www.the-control-freak.com/ClntSrvr/AES/AES.htm