SRTP is an RTP profile intended to provide encryption, message authentication and integrity, and relay attach protection to the RTP data.
SIP TLS protocol aims primarily to provide privacy and data integrity between two or more communicating computer applications.
Verify Your Version of HMP Elements
To implement these security protocols, HMP Elements must be at Version 2.2.9.3 or later.
To update your Voice Elements Platform, you must be enrolled in our support program. If your enrollment has expired, contact Support and we can renew your enrollment and assist in updating your software to the latest version. For more information, see our Support Policy.
Set up HMP Elements to Receive Secure Calls
To receive secure calls, the sender must include a cryptography key in the INVITE for the new call.
This is done by sending an INVITE with a crypto attribute of AES_CM_128_HMAC_SHA1_80, and SAVP in the m=audio line like this:
This method is known as SDES (Session Description Protocol Security Descriptions) and is defined in RFC 4568.
(When using the above method, it is best to have the user or carrier connecting to HMPelements using TLS so that the SDP is encrypted. Otherwise the session key is sent in plain text.) But it will still work with UDP or TCP.
Placing Secure Calls
To PLACE secure calls you must cast the ChannelResource to a SipChannel:
