基于耦合触发细胞自动机的图像加密算法  

Image Encryption Algorithm Based on Coupled Toggle Cellular Automata

作　　者：夏学文[1] 李元香[2] 曾辉[1] 

机构地区：[1]武汉大学计算机学院,武汉430079 [2]武汉大学软件工程国家重点实验室,武汉430072

出　　处：《计算机科学》2009年第2期214-219,共6页Computer Science

基　　金：国家自然科学基金(60473014);国家博士学科点科研基金项目(20030486049)资助

摘　　要：提出了一种基于一维触发细胞自动机的图像加密技术。根据图像文件类型的特点,在加密前对图像进行了简单的预处理,将每个像素点的信息分割成两部分;相应地,密钥也被分成两部分,从而将原始图像信息分成两部分并加密。本加密系统采用的是对称耦合式的触发细胞自动机结构,一方面,加密算法和解密算法可以共享该结构,从而降低了硬件的实现代价;另一方面,基于此结构,对加密后的信息进行了密钥共享和分存,确保只有在同时获得一对密文时才能正确解密。触发细胞自动机的反转规则由子密钥流和图像信息本身共同决定,而且在细胞状态迭代的过程中能自适应地进行调整。密钥空间,即反转规则表,随着细胞自动机邻居半径增大呈指数增长,所以可以根据不同的安全性要求,通过增加细胞自动机的邻居半径来实现。仿真实验证实了该算法的有效性,并得到了较好的加密效果。A novel image encryption algorithm, which is based on one dimension cellular automata （1-D CA）, was proposed. Before encryption, unlike other algorithms, a simple pretreatment was adopted to conceal visual information of original image, which was separated into two parts according to its information characteristic. These two parts were encrypted parallelly. Since secret key was divided into two subkeys corresponding to two subsections of image,only olatai- ning two parts of cipher text could receive decrypt correctly. The key o{ this encryption system is the inverse rules of toggle cellular automata which is not only based on secret key generated by a keystream generator, but also depends on image itself. Furthermore, symmetrical-coupled structure of CAs simplifies the cryptosystem＇s hardware. The proposed image encryption method satisfies the properties of confusion and diffusion due to the wonderful CA substitution as well as the pretreatment. The characteristics of the proposed image encryption system are sharable hardware structure by encryption and decryption, key sharing, self-adaptive inverse rules, very large number of keys and favorable fault tolerance. Simulation results for gray image show that the proposed image encryption method works as out expectations.

关 键 词：图像加密 触发细胞自动机 密钥共享与分存 对称耦合结构 

分 类 号：TP301.6[自动化与计算机技术—计算机系统结构]