基于混沌和DNA随机编码的彩色图像加密算法

Color image encryption algorithm based on chaos and DNA random encoding

提出一种基于基因(DNA)随机编码结合混沌映射的图像加密算法。为解决采用单一编码方式易遭受选择明文攻击的问题,由Logistics混沌映射产生的混沌序列控制完成图像像素值的DNA随机编码。通过使用SHA-384和明文图像来生成Lorenz混沌映射的初始值,置乱部分采用行列置乱和交叉置乱结合的方法,扩散部分采用分组结构来完成像素值的扩散,并对加密后的图像做安全性分析。使用256×256×3的Lena彩色图像进行测试,加密后的图像相邻像素的相关系数均接近0,信息熵均大于7.997,接近理论值8。实验结果表明:所提算法提高了密文的安全性,增大了密钥空间,同时能抵抗各种攻击方式。

An image encryption algorithm based on DNA random encoding combined with chaotic mapping is proposed.In order to solve the problem that the algorithm using single encoding mode to encrypt image is vulnerable to chosen-plaintext attack,the chaotic sequence generated by logistic chaos mapping controls the random DNA coding of the pixel values of the image.The initial value of the Lorenz chaotic mapping is generated by using SHA-384 and plain-image.The scrambling part uses combination of row-column scrambling and cross scrambling.The diffusion part uses grouping structure to complete the diffusion of pixel values.Then the encrypted image is tested for security analysis.Using the 256×256×3 Lena color image for test,the correlation coefficients of the adjacent pixels of the encrypted-image are close to 0,and the information entropy is greater than 7.997,which is close to the theoretical value of 8.The experimental results show that the proposed algorithm enhances the security of the cipher-text,increases size of key space and resists various attack modes.