基于Logistic与标准映射的数字图像加密算法

Image Encryption Algorithm Based on Logistic and Standard Map

基于Logistic和标准映射,提出了新的数字图像加密算法。首先利用离散混沌系统初值敏感性、参数敏感性和具有白噪声统计特性的特点,结合Logistic映射和标准映射设计了置乱变换系统,这种置乱是依赖于密钥的。接着通过一种替代变换使置乱后图像的像素灰度值改变并产生互相依赖,即将每一像素值扩散到其它像素中去。这样,加密算法便具有置乱、替代、扩散等加密系统的基本要素。实验仿真和分析表明,该算法密钥空间大,易于实现,有较好的加密效果和统计特性。

Based on Logistics and Standard Map,a new image encryption algorithm was proposed.By using the properties of chaotic map such as sensitive to initial values,sensitive to parameters and the statistic specialty of white noise,the confusion system was designed through discrete chaotic map and standard map.This confusion is dependent on the secret keys generated by a different chaotic system.Then changed the pixel values of encrypted image through the substitution system and made pixels associated with each other.At the same time,every pixel value was diffused to others.The system contains confusion,substitution and diffusion,which are necessary factors for a good cryptosystem.The experimental simulation and analysis illuminate that the algorithm has such advantages：larger key space,easily realized and perfect statistical characteristics.