基于时空混沌系统的彩色图像加密算法

Color image encryption algorithm based on spatiotemporal chaotic system

提升混沌系统的复杂性,对保证基于混沌的加密算法的安全性有重要意义。将分段Logistic映射引入到时空混沌模型中,有效增加了时空混沌模型的复杂性,基于此模型提出了彩色图像的加密方法。在加密算法中,为了增强算法的安全性,以时空混沌系统的状态值作为置乱方程选择的依据,同时考虑了彩色图像R、G和B三个分量之间的相互置乱;利用时空混沌模型产生的复杂数字序列对置乱后的图像进行扩散操作;经多轮的置乱和扩散操作后,产生最终的加密图像。性能分析以及仿真实验的结果表明该算法具有良好的安全性,能够有效满足图像在网络中安全传输的需求。

It is important for chaos-based encryption algorithms to enhance the complexity of chaotic systems. Introducing the piecewise logistic map（PLM） to the spatiotemporal chaotic system, it could effectively enhance the complexity of the spatio- temporal chaotic system. This paper proposed a color image encryption algorithm based on the spatiotemporal chaotic system. In the proposed methods, the permutation function was determined by the status value of the spatiotemporal chaotic system. In order to improve the security, the R, G and B components of color image were substituted in the permutation stage. Then,it used the complicated digital sequences generated from the spatiotemporal chaotic system to diffuse the permuted image. The encrypted image was finally produced by the multi-round iteration of the ＂permutation-diffusion＂ operations. Performance analysis and simulation test results show that the proposed algorithm not only has high security but also can satisfy the require- ment of transmitting image safely over the network.