对Kwok混沌图像加密算法的安全性分析  

Security on Kwok Chaotic Image Encryption Scheme

作　　者：谢邦勇[1] 王德石[1] 

机构地区：[1]海军工程大学兵器工程系,武汉430033

出　　处：《武汉理工大学学报》2009年第24期99-101,105,共4页Journal of Wuhan University of Technology

基　　金：国家自然科学基金(10272113)

摘　　要：针对Kwok等人提出的图像加密算法,研究了算法使用的密钥流发生器的周期特性、弱密钥和等效子密钥之间的相互独立性。通过随机选择样本点进行大规模迭代计算,表明密钥流的平均周期远小于预期值。基于三维Cat映射的仿射特性,在已知初始密钥流的条件下,通过搜索3组符合要求的初始密钥流,就可以恢复算法的等效密钥。表明Kwok算法的设计并不成功。The security of an image encryption scheme based on modified version of skew tent map and high dimension cat map is analyzed. Cycle properties of modified skew tent on digital computer, a lot of weak keys and independency of equivalent sub keys are major research issues of the paper. With random chosen sample point, Large scale chaotic iteration have shown that the average periods of random key stream far small than the expected. Based on the affinity of 313 chaotic cat map, equivalent keys can be found by search three groups of coincident initial key stream with the known initial key stream. So, from strict cryptographical view, algorithm does not reach its design goals.

关 键 词：混沌密码 斜帐篷映射 猫映射 图像加密 加密算法 密码分析 

分 类 号：TN918.1[电子电信—通信与信息系统]