Based On Mpeg4 Video Encryption Algorithm And Its Dsp

With the development of network technology, wireless communication and multimedia technology, the multimedia data is transmitted frequently in the network, which makes eavestropping and modification easy, therefore heavily threaten the security of the information. The more and more importance of the multimedia information security has sparkled an avalanche research of the encryption algorithm of multimedia data. In this thesis, the disadvantages of the tranditional ciphers have been pointed out and by use of the features of MPEG video data stream. Several video encryption algorithms have been studied and transplanted to a DSP evaluation board with DM642 processor. The main work of the thesis is listed as follows:First a simplified version of XviD package that is based on MPEG4 video codec standard was obtained. Then, the VEA (Video Encryption Algorithm) partial video encryption algorithm and an encryption algorithm that scrambles the table of entropy coder were designed, analyzed, implemented and tested. The later encryption algorithm was further integrated into the XviD codec. The XviD encoder and decoder were encapsulated respectively to make the whole software system modularized and hierarchical. Finally, the encoder and decoder are both realized on a processor DM642. Simulation and Emilution experimental reseals are also reported in the thesis. Finally, the decoder system based on the DM642 was optimized. The experiment results show that the performance in terms of real-time processing is enhanced.