基于改进型二维映射和DNA编码的图像加密

Image encryption based on improved two-dimensional mapping and DNA coding

为了增加图像加密的安全性,提出一种基于改进型二维映射和脱氧核糖核酸(Deoxyribo Nucleic Acid,DNA)编码的图像加密算法。首先,结合Logistic映射、Sine映射和Henon映射的特点,设计了一种改进型二维离散混沌映射,具有较好的随机性且为满映射,适用于图像加密;然后,基于该混沌序列对图像明文进行DNA编码,通过DNA运算实现了图像的置乱和扩散,完成了图像的加密。仿真实验结果表明,该加密算法的像素数变化率(Number of Pixels Change Rate,NPCR)和统一平均变化强度(Unified Average Changing Intensity,UACI)均接近或高于理论计算值,峰值信噪比(Peak Signal to Noise Ratio,PSNR)小于10,说明改进算法的明文和密钥敏感性高,能有效抵御差分攻击。

An image encryption algorithm based on improved two-dimensional mapping and Deoxyribo Nucleic Acid(DNA)coding is proposed for increasing the security of image encryption.Firstly,combined with the characteristics of logistic map,sine map and Henon map,an improved two-dimensional discrete chaotic map is designed,which has good randomness and is a full map,especially suitable for image encryption.Based on the chaotic sequence,the image plaintext is encoded by DNA,the image is scrambled and diffused by DNA operation,and the image encryption is implemented.Simulation results show that both the Number of Pixels Change Rate(NPCR)and the Unified Average Changing Intensity(UACI)values are close to or higher than the theoretical calculation value,and the Peak Signal to Noise Ratio(PSNR)is less than 10,indicating that the improved algorithm has high sensitivity of plaintext and key,and can effectively resist differential attacks.