Added functionality that allows for encrypted RTP audio communications between SIP devices, known as SRTP (RFC-3711). SRTP works in conjunction with the TLS protocol for SIP traffic to secure all communications to and from the phones. ZRTP (RFC-6189) is not supported.
Enabling TLS AND SRTP
SRTP at this time must be enabled by support. Please contact support and request SRTP to be enabled including the domain name.