基于自适应和多混沌系统的彩色图像压缩加密算法

Color Image Compression and Encryption Algorithm Based on Self-adaption and Multiple Chaotic Systems

为了保护彩色图像信息的安全并便于保存和传输,提出了一种基于自适应和多混沌系统的彩色图像压缩加密算法.该算法首先利用量子混沌系统对按8×8分块后的整个图像进行置乱.然后,进行图像的RGB分离并转换为YCrCb,对YCrCb分量分别进行DCT变换和量化,再利用猫映射对量化后的YCrCb分量进行置乱,最后根据彩色图像自身的像素分布特征获取初始值,以DC系数和AC系数矩阵各行的均值作为操作数对Logistic-sine复合混沌系统进行扰动产生密钥,利用初始值和密钥自适应地改变DC系数和AC系数并进行多轮扩散.理论分析和仿真实验表明,该算法具有足够大的密钥空间,压缩加密效果好、安全性高,可以广泛地应用于多媒体数据的保密通信.

In order to achieve effective protection of the color image information,a new color image compression and encryption algorithm is proposed based on self-adaption and multiple chaotic systems.Firstly,the blocks of 8×8pixels of the image were scrambled by the quantum chaotic system globally.Then the RGB components were separated and converted to YCrCb components,and then DCT transformation and quantization were both executed.YCrCb blocks were scrambled and quantized by using the cat map.Finally,initial values were gotten according to pixel distribution of the color image,the means of each row of DC coefficient matrix and AC coefficient matrix were taken as operand to disturb Logistic-sine composite chaotic system to generate the keys,DC coefficient matrix and AC coefficient matrix were changed through several rounds of proliferation using the initial values and the keys adaptively,and the ciphered image appeared.Theoretical analysis and simulation results show that this algorithm with a sufficiently large key space not only has good performance on compression and encryption,but also has the high safety.The algorithm can be widely used in secure communication of multimedia data.