利用逻辑映射和混沌线性分块变换的图像加密算法

摘要

为提高图像加密算法的置乱、扩散功能和密码学性能,基于线性分块变换和混沌系统,提出将两个混沌系统和S盒相结合,实现更好的混沌和扩散.首先是基于混沌映射的扩散阶段;为提升加密性能,利用性能优异的S盒进行代换操作,利用基于混沌逻辑映射进行扩散;为提高算法的统计性能,利用置换函数完成分块置换.仿真结果表明,与其它同类算法相比,该算法的敏感性、信息熵和相关性更优,可有效抵御多种攻击,密钥空间更大,所需总操作数更少.%To improve the scrambling,diffusion function and performance of image encryption algorithm,based on linear fractional transformation and chaotic system,two chaotic systems and S-box were combined to achieve better chaos and diffusion.The first step was based on the diffusion stage of chaotic mapping.To significantly enhance the performance of encryption,the substitution operation of S-box was adopted and chaotic logistic mapping was used for diffusion.To improve the statistical performance of the encryption algorithm,the replacement function was applied to complete the block replacement.Simulation resuits show that,compared with other similar algorithms,the proposed algorithm is better in sensitivity,information entropy and correlation.The proposed algorithm can be effective against a variety of attacks.In addition,the key space is larger,and the total number of operations required is less.