The Research Of Multimedia Information Encryption Algorithm And System Design

With the fast development of network and multimedia technology, digital multimedia information has become a main way for information communication. Thus, how to protect the security of multimedia information is hot focus nowadays.Due to the properties of chaotic system such as the sensitivity to initial parameters, the ergodicity and the statistics property of white noise, it is used in multimedia information encryption in this paper. In the part of image encryption, chaotic map based on Kolmogorov flow is used to permute. Changing the traditional stream-cipher, new chaotic pseudo-random sequence generator based on the theory of product cipher is presented to substitute the pixel. Based on it, linear map to confuse the pixel is presented further, withstanding statistical attack. The algorithm has a large space of the key, which can be proven by detailed analysis of the performance index, and can withstand chosen-text/cipher attack. In the part of voice encryption, spatiotemporal chaotic system (OCOML model) and LFSR are used to generate multidimensional pseudo-random sequence. This sequence has a longer period, better randomicity, passing the verification of FIPS 140-2 security requirements. Using the key stream generated by it to encrypt the voice gets a better security.Finally, VHDL is used to descript the algorithm upwards. Multimedia information encryption/decryption system is designed then. Software platform includes read, write and storage of the multimedia-file and interface design. Hardware platform includes data communiacation, voice processing and the system of FPGA. RS232 and EPP mode are used in tte part of the data communiacation. Voice signal collection and magnify, AD/DA conversion and power magnify circuits are integrated in the part of the voice processing. Debugging on the whole software and hardware expresses the whole scheme is reasonable and feasible, having a better security and higher throughput. The whole system has a higher speed and satisfies the need of the project in pratical.