作　　者： ; ;

机构地区： 汕头大学理学院数学系

出　　处： 《汕头大学学报（自然科学版）》 2016年第2期50-58,共9页

摘　　要： 对一种基于改进广义cat映射的彩色卫星图像加密算法进行安全性分析,并提出相应的选择明文/密文攻击和已知明文攻击方法.该算法改造了一般广义cat映射,通过增加一个非线性项使得一般广义cat映射具有更好的混沌特性;并利用改进广义cat映射进行图像置乱,然后用复合混沌映射对置乱后的图像进行扩散运算,实现图像加密.经过理论分析发现该算法存在两方面不足.一方面是扩散过程过于简单,采用简单的整幅图像的异或运算;另一方面是采用改进广义cat的置乱过程与明文无关.这两方面的不足,使得算法很容易受到破译.理论和仿真实验均表明该算法无法抵抗选择明文/密文攻击和已知明文攻击. A color satellite image encryption algorithm based on improved generalized cat mapping was proposed recently. The algorithm modified the generalized cat mapping by adding a nonlinear term to make the generalized cat mapping with more chaotic natures. Three color components of color images were scrambled by using the improved generalized cat mapping. The diffusion for scrambled image is carried out by using compound chaos mapping. In this paper, three kinds of cryptanalysis on this image encryption algorithm are devised, including chosen plaintext attack, chosen ciphertext attack and known plaintext attack. There are two shortcomings in this encryption algorithm according to the theoretical security analysis. The diffusion processing only uses a simple XOR operation on the whole image. The scrambled image is independent on the plain image. Both theoretical and simulation experiments show that the encryption algorithm cannot resist chosen plaintext/ciphertext attacks and known-plaintext attacks.

关 键 词： 混沌映射 图像加密 选择明文攻击 选择密文攻击 已知明文攻击

领　　域： [自动化与计算机技术] [自动化与计算机技术]