基于多混沌系统的分组结构灰度图像加密算法

摘要

Based on two types of chaotic mapping models,the general Arnold map and unidirectionalcoupled maps lattice,a gray image encryption algorithm with packet structure is proposed.This algorithm firstly makes the cyclic shift operations on the initial key to obtain multiple round keys,and then,uses the generalized Arnold mapping and unidirectional-coupled maps lattice to encrypt the image iteratively.During the encryption process of each round,two encryption subkeys generated from the round key are used respectively to the generalized Arnold mapping and unidirectional-coupled maps lattice systems,thus,the algorithm can get better security performance.Experimental simulation results show that,the proposed algorithm works well in the evaluation indexes,such as the gray histogram of encrypted image,the average value of gray variation,the correlation coefficient of adjacent pixels and the sensitivity to key space.%基于广义猫映射和单向耦合映射格子二种混沌映射,给出一种分组结构的灰度图像加密算法.先对初始密钥进行循环移位操作,得到多组轮密钥,再采用广义猫映射和单向耦合映射格子对图像进行迭代加密.在每轮加密过程中,由轮密钥产生两个加密子密钥,分别用于广义猫映射和单向耦合映射格子系统,以增加算法的安全性能.实验仿真和分析表明,加密图像的灰度直方图、灰度变化平均值、相邻像素相关系数及密钥空间敏感性等评价指标性能良好.