摘要
针对低维混沌系统复杂性低、应用在图像加密中效果差等问题,通过相图、分岔图、Lyapunov指数谱以及谱熵复杂度等方面探究了一个四维超混沌系统的动力学特性及其加密应用.仿真结果表明上述系统的混沌状态分布在较大的参数范围内并且具有较大的复杂度值,说明上述系统能够很好的应用于图像加密.为此设计了一种基于四维超混沌的图像加密方案.算法主要利用改进的Arnold变换将明文图像的像素点位置进行扰乱,并通过加取模运算对置乱后的图像进行扩散,得到加密图像.最后通过密钥空间、相邻像素间相关性、信息熵、直方图以及差分攻击等方面分析了算法的安全性能.实验结果表明,上述加密算法不仅能够有效地对图像进行加密而且具有较高的安全性能.
Abstract
In order to solve the problems of low complexity and poor application in image encryption of low-di-mensional chaotic system,this paper explored the dynamic characteristic of a four-dimensional hyperchaotic system and its encryption application through phase diagram,bifurcation diagram,Lyapunov exponential spectrum and spectral entropy complexity.The simulation results show that the chaotic state of the system is distributed in a large parameter range and has a large complexity value,indicating that the system can be well applied to image encryption.To this end,this paper designed an image encryption scheme based on four-dimensional hyperchaotic system.The al-gorithm mainly used the improved Arnold transform to disturb the pixel point position of the plaintext image,and dif-fused the image after the image operation was performed,and the encrypted image was obtained.Finally,the safety performance of the algorithm was analyzed by key space,adjacent pixel relationship,information entropy,histogram,and differential attack.The experimental results show that the encryption algorithm can not only effectively encrypt the image but also high security.
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