基于超混沌和扩展Cat映射的实时视频流加密算法

为提高密码的抗攻击性,利用超混沌系统随机性好、可确定再生,且密钥空间较大的特性,提出了一种基于四维连续超混沌系统和扩展Cat映射的实时视频流加密算法。该算法将流密码和块密码相结合,实现视频流的实时加密,克服了现有的多数基于混沌系统的视频加密算法不能抵抗已知明文攻击和密钥空间小的缺点。流密码采用四维连续超混沌方程进行加密,可同时生成4个混沌序列,既提高了加密速度,又增加了密码的复杂度。块密码应用扩展的Cat映射,通过将信息置乱进行加密,Cat映射对初值和参数敏感,置乱效果好,且是双射函数,适合于信息的加密。实验结果表明,该算法安全性高,密钥空间大,能抵抗统计分析、差分攻击,密钥敏感性高,加密速度快,可达到3 Mb it/s,满足实时处理的要求。同时,该算法与视频压缩算法相独立,实现简单。

Real-Time Video Stream Encryption Algorithm Based on Hyperchaos and Extended Cat Map

A real-time video stream encryption algorithm based on hyperchaos and extended cat map is proposed.A four-dimensional hyperchaotic system is used to generate stream cipher and the extended cat map is employed to construct block cipher.The video data are encrypted by the block cipher and the stream cipher,thereby significantly increasing the key space,the resistance to statistical and differential attacks and providing high key sensitivity,and fast encryption speed.The experimental tests carried out with detailed analysis,demonstrate that the proposed algorithm provides high security for real-time video stream with fast encryption speed,and is simple to realize by software.It is independent of any video compression algorithms,and it will not be limited by the format of encrypted video,which is one important merit of the proposed scheme compared with other video encryption systems.