Design And Implementation Of VoIP Media Security Protocols Based On Voice Gateway

VoIP becomes more and more attractive in global telecommunication market withgood performance, low cost and good support for multifunction. However, RTP,designed for transporting voice media stream, does not have Qos mechanism, packetsreliability and order assurance. Therefore, media streams transported by RTP protocolexist security issues, such as eavesdropping, voice media stream confusion, replayattacks, etc.This paper focuses on the VoIP Media Security problem of Voice Gateway. In orderto settle RTP security problems, SRTP and SDES, one of key management protocols,were learned deeply. Then, based on RFC4568, this paper implementes SRTP securityparameter encoding and decoding, key negotiation with SIP message exchange toprovide key,encryption algorithm and authentication algorithm for SRTP encryption andauthentication. Based on RFC3711, this paper implements that to-be-sent packetstransform into SRTP/SRTCP packets with encryption and authentication operation, andRTP/RTCP recover from received SRTP/SRTCP packets with replay attack detection,authentication processing and decryption. These implementations ensure RTP packetsconfidentiality, integrity, and reliability.This paper designs function and performance test cases, tests function andperformance of SRTP function supported by Voice. Test result shows that VoiceGateway supports SRTP in multiple voice service, voice performance and quality meetrequirement.