Secure Media Recording and Transcoding with the Session Initiation Protocol
Dan Wing, Steffen Fries, Francois Audet, Alan B. Johnston, Hannes Tschofenig · 2008
Many Secure RTP (SRTP) key exchange mechanisms do not disclose the SRTP session keys to intermediate SIP proxies. Howevr, these key exchange mechanisms cannot be used In environments where transcoding, monitoring, or call recording are needed. This document specifies a secure mechanism for a cooperating endpoint to disclose its SRTP master keys to an authorized party.