快速置乱耦合3D混沌映射的图像加密算法研究

Study on Image Encryption Algorithm Based on Faster Permutation Coupled with 3D Chaotic Map

针对当前3D混沌映射加密算法的安全性不高,且其置乱过程的计算量大,置乱性不稳定,以及置乱方法不具有通用性等缺陷,设计了一种快速通用置乱方法,并将混淆与扩散机制同时引入进来,提出了一种新的3D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3D混沌映射,得到一个序列,该序列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3D混沌映射,得到三元一维伪随机数组,并借助密钥流机制量化该数组,得到新序列,利用该新序列根据扩散机制对混淆后的像素进行扩散处理。借助MATLAB仿真软件对该算法及其他3D算法进行对比仿真。结果显示:与其他3D算法相比,该算法安全性更高,置乱速度更快,计算效率更高,且其密钥空间巨大。

To these lacks of image encryption of current 3D chaotic map such as low security, the large amount of calculation during permutation, and not universal resulting in low computation efficiency, the fast scrambling method is designed, and the mixing and diffusion mechanismare simultaneously introduced into this algorithm to propose the image eneryption 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 is used to permute the initial image to change the posi- tion of pixel, the initial external key is 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 is iterated again to get a three triple 1 D pseudo-random array, and the key stream mechanism is used to quantity the array to get one new array, using the new array to diffusion the confused pixel. The MATLAB simula- tion software is used to compare the encryption algorithm proposed by this paper and other 3D image algorithm, the results show that, compared with other 3D algorithm, the security of this image encryption algorithm is higher, the permutation speed is faster, and the computation efficiency is higher, as well as the key space is huge.