基于改进的复合混沌系统的图像加密算法  

Image encryption algorithm based on improved complex chaotic system

作　　者：魏慧 李国东[1] 许向亮 WEI Hui;LI Guo-dong;XU Xiang-liang(School of Statistics and Data Science,Xinjiang University of Finance and Economics,Urumqi 830012,China)

机构地区：[1]新疆财经大学统计与数据科学学院,新疆乌鲁木齐830012

出　　处：《微电子学与计算机》2020年第4期19-25,共7页Microelectronics & Computer

基　　金：国家自然科学基金(11461063);新疆维吾尔自治区自然科基金(2017D01A24);新疆财经大学基金(2019XTD002)。

摘　　要：针对单一混沌系统加密不足的问题:主要提出的算法是基于改进的LCL复合混沌系统和DFT变化的图像加密算法.首先对图像DFT变换,应用高维Lorenz系统产生的混沌序列进行随机组合排列,将得到的一组索引序列结合改进的Cat系统对明文图像进行置乱;其次,采用超Lorenz混沌系统设计得到Logistic映射的伪随机序列,将其进行异或处理得到密文图像;为了达到加密效果更优良的目的,重复以上步骤进行循环加密处理.仿真结果表明本文设计算法具有优良的加密效果,密钥空间大、明密文敏感性强、能有效抵抗统计攻击等.Aiming at the problem of insufficient encryption of a single chaotic system,the main proposed algorithm is an image encryption algorithm based on improved LCL composite chaotic system and DFT variation.Firstly,DFT transformation of images is carried out,chaotic sequences generated by high-dimensional Lorenz system are randomly combined and arranged,and a group of obtained index sequences are combined with an improved Cat system to scramble plaintext images;Secondly,the pseudo-random sequence of Logistic map is designed by using hyper-Lorenz chaotic system,and the encrypted image is obtained by XOR processing.In order to achieve better encryption effect,repeat the above steps for cyclic encryption.The simulation results show that the algorithm designed in this paper has excellent encryption effect,large key space,strong sensitivity to plaintext,and can effectively resist statistical attacks.

关 键 词：二维离散傅里叶变换 混沌映射 信息熵 图像加密 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]