Research On The Security Mechanism Of Teleconference System Based On SIP Protocol

With the development of IP technology, various multimedia services based on IP networks are popularized rapidly. The development of teleconference system based on IP is very fast.The teleconference application in the traditional telecom network is mainly based on H.320 or H.323 standards. Its complex realization and huge investment make it difficult to apply to public services. Moreover, the close architecture and low bandwidth of the traditional telecom networks are not suitable for the fast development on multimedia applications. In this case, teleconference which is very convenient and cheap is popular with people.The teleconference of the paper is based on Session Initiation Protocol (SIP), SIP is an application-layer signaling protocol used to establish, modify, and terminate multimedia sessions. Compared with H.323, SIP is more tightly integrated with Internet protocols and has a lot of advantages. Now SIP is widely used and attracting more and more attention. But SIP has not developed the corresponding security mechanism. It brings great security risks to the teleconference system Therefore,the studies of SIP security is becoming very important.This paper analyses SIP protocol and the structure and the main flows of the teleconference firstly. Then it researches security problems about SIP and HTTP digest, TLS and S/MIME. Based on them, this paper designs the security mechanism for the teleconference mentioned on the paper. The mechanism contains authentication and encrypt mechanism. HTTP digest, TLS and S/MIME are used to the security mechanism for the security of transmission-layer and application-layer. In the end of the paper, HTTP digest is realized and tested.This security mechanism assures the authentication between conference terminal and conference server. Besides, the message header and message body of conference are encrypted. The security of the teleconference was improved greatly.