基于混沌映射的图像加密硬件实现结构  

Implement of hardware structure of an image encryption system using chaotic maps alternately

作　　者：张翌维[1] 沈绪榜[1] 郑新建[1] 张洵颖[1] 

机构地区：[1]西安微电子技术研究所,陕西西安710054

出　　处：《华中科技大学学报（自然科学版）》2008年第6期84-88,共5页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：陕西省重大科技创新专项基金资助项目(2005ZKC-2-10-02)

摘　　要：为了使图像加密硬件化和实用化,针对图像加密系统所需的置换、替代和扩散3种基本要素,提出了一种采用双RAM连接,加/解密过程多轮次、可复用的硬件实现结构.该实现结构通过地址产生器得到置换地址,与地址计数器配合完成像素的位置置换;通过灰度扩散与像素替代单元完成灰度的扩散与替代.验证中采用广义猫映射进行像素位置置换,将单向耦合映射格点用于像素的替代,并与灰度扩散相结合,两种混沌映射多轮次交替使用.分析和实验证明,该结构具有复用性好、吞吐率高且面积节约等特点.现场可编程门阵列验证表明,在200 MHz时钟频率下,进行4轮加/解密时的吞吐率分别达到4.17 Mbyte/s和3.85 Mbyte/s.Featuring dual-RAM connection, reusable data-path in each round of encryption or decryption, novel hardware architecture was proposed to apply the image encryption to hardware devices. Within a pixel block, general cat-map and OCML （one-way coupled map lattice） were alternately used for permutation, diffusion and substitution. For the general cat-map, an address generator was adopted to obtain scrambling destinations, which resulted in pixel＇s position permutation cooperated with the address counter. For the OCML, a diffusion and OCML matrix substitution unit was designed to diffuse and substitute each pixel＇s gray-scale. The cryptanalysis indicates that the algorithm is robust to many forms of attacks, and the proposed hardware structure bears good reusability, high throughput and compact area. FPGA implementation shows that when system frequency is 200 MHz, the throughput under 4 rounds of encryption and decryption reaches 4.17 Mbyte/s and 3.85 Mbyte/s respectively.

关 键 词：图像加密 混沌映射 分组密码 现场可编程门阵列(FPGA) 猫映射 灰度扩散 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]