A Security Solution Of H.323 Videoconferencing System

The security of videoconferencing system is becoming the research focus and increasingly important. In this paper, a security solution based on H.323 videoconferencing system is presented.The videoconferencing system includes Certificate Authority, MCU, Gatekeeper and Terminal. Certificate Authority is in charge of the registration and management of users'certificate; MCU switches video, audio and data signal; GateKeeper manages call procedure and teminal authentication; Video terminal makes compress and decompression process, it also in charge of encryption and decryption process.The solution proposes a one-way authentication method based on X.509 Digital Certificate to solve the security problem of username-password authentication method. Certificate Authority implements registration and management according to the Certificate Management Protocol. Before the videoconferencing, Gatekeeper should authenticate users'validity and manage users'operation.The solution advances a video steam encryption method using two-dimensional chaotic stream encrypting algorithm. It selectively encrypts signs of DCT coefficients.In conclusion, this article tests the chaos streaming and encryption system. The test of chaos streaming shows that it is highly independent and identically distributed; The test of encryption system demonstratesthe the security, real-time performance and fault-tolerance of the solution.