Resolution
Media encryption using Secure Real-Time Transport Protocol (SRTP) delivers protection by encrypting the voice conversation, rendering it unintelligible to internal or external eavesdroppers who have gained access to the voice domain. Designed for voice packets, SRTP supports the Advanced Encryption Standard (AES) encryption algorithm and is an IETF RFC 3711 standard.
As long as any third party endpoint supports RFC 3711, things should work fine.
