libsrtp: libsrtp (Secure RTP libraries) libsrtp: libsrtp: libSRTP is the Open Source Secure RTP library from Cisco Systems, Inc. libsrtp: RTP is the Real-time Transport Protocol, an IETF standard for the libsrtp: transport of real-time data such as telephony, audio, and video, libsrtp: defined by RFC 3550. Secure RTP (SRTP) is an RTP profile for providing libsrtp: confidentiality to RTP data and authentication to the RTP header and libsrtp: payload. SRTP is an IETF Standard, defined in RFC 3711, and was libsrtp: developed in the IETF Audio/Video Transport (AVT) Working Group. This libsrtp: library supports all of the mandatory features of SRTP, but not all of libsrtp: the optional features.