Improvement of Security and Feasibility for Chaos-Based Multimedia Cryptosystem

摘要

Nonlinear dynamic filter (NDF) has been used in chaos-based multimedia cryptosystem. However, our study shows that the key of randomized arithmetic coding (RAC) based on NDF can be successfully recovered under chosen plaintext attack. Moreover, current ciphertext block can't be decoded unless preceding plaintext is available. In order to enhance the security and feasibility used in multimedia applications, the algorithm is improved by building a new correlation between ciphertext and coefficients. Its security is enhanced that can effectively resist chosen plaintext attack. Its feasibility is also improved that can decode ciphertext block without availability of preceding plaintext with which a user can play multimedia data starting at any place. The analysis and simulations show that the improved algorithm can evidently enhance both security and feasibility.