基于混沌映射的图像快速加密改进算法

Image Fast Encryption Algorithm Based on Chaotic Map

摘要:

针对当前的三维混沌映射加密算法存在安全性不高,加密速度慢以及密钥空间小等不足,提出了一种新的三维混沌映射图像加密算法；首先利用快速置乱方法置乱初始图像,以改变像素位置；利用三维Chen系统结合像素值变换函数所生成初始外部密钥迭代三维混沌映射,得到一个序列,由此根据混淆机制对置乱图像像素值进行混淆；改变外部密钥,再迭代计算三维混沌映射,得到三元一维伪随机数组,借助密钥流机制量化该数组,得到新数组,由此根据扩散机制对混淆后的像素进行扩散处理；采用酷睿3.5 GHz双核CPU的PC机和MATLAB仿真平台,输入256×256的明文图像实验,置乱100次所用时间为78.67 s,在灰度平面内其相关性约为-0.001 652,表明该算法高度安全,密钥空间巨大,加密速度快,用于图像快速加密是可行、有效的。

Abstract:

To these lacks of image encryption of current 3D chaotic map such as low security, low encryption speed and small key space, the fast scrambling method was designed in this paper, and the mixing and diffusion mechanism were simultaneously introduced into this algorithm to propose the image encryption algorithm based on the fast scrambling integration with 3D chaotic map to strengthen the security of the algorithm for well overcoming above defects. Firstly, the fast scrambling method was used to permute the initial image to change the position of pixel; the initial external key was obtained by 3D Chen system with transform function of pixel value to confuse the pixel of the permutation image under the mixing mechanism; changing the initial external key , the 3D chaotic map was iterated again to get a three triple 1D pseudo-random array, and the key stream mechanism was used to quantity the array to get one new array, using the new array to diffusion the confused pixel. Using Core Duo 3.5 GH PC machine with dual-core CPU and MATLAB simulation platform, inputting 256*256 pixel image experiments expressly, it uses 78.67 s scrambling 100 times, its relevance is -0.001 652 in the gray plane about, The results showed that:this image encryption algorithm has a good encryption property such as highly secure, huge key space, and fast encryption speed. 