基于函数展开与超混沌系统的图像加密

为有效保护数字图像的安全，提出一种基于小波展开函数与超混沌系统的数字图像加密算法。利用小波展开函数对图像进行置乱，通过超混沌系统扰乱原图像与加密图像之间的关系。在求解超混沌系统混沌序列的四阶Runge-Kutta公式中，插入多个参数以扩大参数空间。模拟实验结果表明，加密后图像灰度值分布伪随机性较好。

Image Encryption Based on Function Expansion and Hyperchaotic System

In order to protect the security of a digital image effectively,this paper proposes an image encryption algorithm based on wavelet expansion function and hyperchaotic system.The pixel locations of the image are scrambled with a wavelet function,and the relationship between the original image and the encrypted image is disrupted with hyper-chaos system.The many parameters are inserted in four-step Runge-Kutta method in which chaos sequence of hyper-chaos system is gotten,to expand the space of parameter.Simulation experimental result show that the random behavior of gray value distribution of the encrypted image is better and the method can defends attacks.