时间延迟函数耦合一致分布混沌映射的视频流加密算法研究

ON VIDEO STREAM ENCRYPTION ALGORITHM BASED ON TIME-DELAY FUNCTION COUPLING UNIFORMLY DISTRIBUTED CHAOTIC MAP

由于现有的视频流加密算法都没考虑时间延迟特征而导致加密序列的自相关性较高,降低其安全性;且其在计算效率与安全性之间存在矛盾。对此,设计了时间延迟函数和一致分布Logistic映射,并将MEPG技术引入进来,提出了时间延迟函数与一致分布混沌映射相融合的MEPG视频流加密算法。采用块加密结合流加密,可解决加密速度与安全性之间的矛盾;并将时间延迟引入到超混沌序列中,消除该序列的自相关性;在加密过程中嵌入MEPG编码,实现实时性。利用MATLAB对该算法以及其他几种算法进行对比仿真,结果显示:与其他算法相比,该加密算法的安全性更高;考虑时间延迟特征的超混沌序列的自相关性更低。

Since all of the current video stream encryption algorithms do not take the time delay feature into consideration, this results in higher autocorrelation of the encryption sequence and lowering its security; besides there is the contradiction between its computation efficiency and security. To address this issue, we design the time delay function and the uniformly distributed Logistic map, and introduce the MEPG technology to propose the MPEG video stream encryption algorithm which ingrates the time delay function and uniformly distributed chaotic map. By combining block encryption with stream eucryption, the contradiction between the encryption speed and security can be solved; Furthermore, it introduces the time delay into the hyperchaotic sequences to reduce the autocorrelation; In encryption process it embeds the MEPG encoding to achieve the real time property. The MATLAB is used to carry out contrasted simulation between the proposed algorithm and other video stream algorithms, results show that compared with other encryption algorithms, the algorithm proposed in this paper has higher security ; the autocorrelation of the time delay-considering hyperchaotic sequence is lower as well.