基于混沌的图像加密方法在安全性、适应性上具有优势.文中在对原有的混沌图像加密算法安全性分析的基础上,提出了一种基于Logistic和Chebyshev双混沌映射的数字灰度图像加密算法.借助基于明文产生的辅助密钥、初始密钥以及由双混沌系统产生交替分段相互置乱的密码序列是本算法的核心.计算机仿真及统计特性、安全性分析表明,该加密算法具有良好的加密效果和较高的安全性能,密钥空间达到255×10120.

As the image encryption based on chaos is of high security and adaptability,this paper analyzes the security of the conventional image encryption algorithms based on chaotic systems and proposes a new image encryption algorithm based on diploid Logistic and Chebyshev chaotic maps.The auxiliary and the initial secret keys based on original image,as well as the reciprocally-disordered cipher sequences alternated in subsection and generated by the diploid chaotic systems,are the kernel parts of the proposed algorithm.Both the simulated and statistical results and the security analysis show that the proposed algorithm is of excellent encryption effect and high security,with a key space being up to 255×10120.