A Research Of Chaotic Encryption Algorithm Of Multimedia Information

With development of network and multi-media, information security technology is becoming one of the hot topics. Image and video are the important information carries, in the multi-media domain. It is a new field that secret communication of image/video based on the chaos theory. Chaotic encryption applied to network and secure communication provides a new way to solve the information security problems. This paper described the chaos theory, summarized the research status of image and video encryption, and studied the encryption algorithm of digital image/video based on chaos with theoretical analysis and numerical experiment.This paper discussed several typical algorithms about block cipher and stream cipher based on chaos, analyzed security performance of chaos cipher, and presented some encryption algorithms on image/video.In the image encryption, the two algorithms based on chaotic were presented. In space domain, encryption and decryption keys were obtained by Chebyshev map, which confused the plain-text with random input keys. Then Logistic map and Nonlinear Chaotic Algorithm (NCA) were used to confuse the plain-test and to shuffle the position of the plain-test respectively. Simulation experiments were made to show the security and efficiency. In frequency domain, a chaos-based weight variation of Huffman tree for image encryption algorithm was proposed. In the process of the entropy coding, DC coefficients were encrypted by the weight variation of Huffman tree with the double Logistic chaos and AC coefficients were encrypted by the indexes of codeword. The security, complexity and compression ratio of the algorithm were analyzed. Simulation results showed that this algorithm had high security,low complexity,efficiency encryption and decryption, and tiny impact on the compression efficiency.In the video encryption,according to the features of AVI, a new chaotic encryption algorithm was presented to protect video security. The algorithm combined the Lorenz system map with Double Coupling Logistic map to generate the complicated chaotic sequences, and then used XOR operator to encrypt the multimedia AVI files. The results of simulation experiments, security analyses and efficiency analyses indicated that the algorithm had large key space and the capacity to resist the statistical analysis, differential attack, and it could provide an efficient and secure way for real-time video encryption and transmission.