一种基于复合混沌序列的图像加密方法

针对低维度混沌系统的密钥空间小、加密系统安全性较低的不足。提出一种由sine混沌改变均匀分布logistic混沌排列次序形成复合混沌序列的图像加密方法。首先，产生服从均匀分布的logistic混沌序列，用sine混沌序列重排该序列整数化后的重复部分，以此无重复数值的复合混沌序列进行像素位置置乱；之后，由于仅进行位置置乱不能改变图像的灰度统计直方图特征，用sine混沌重排整个logistic混沌序列形成复合混沌序列，以此进行像素扩散完成图像加密。对方法安全性从密钥空间、密钥敏感性、差分分析、统计直方图、相邻像素相关性、信息熵方面进行了测量。实验结果表明该方法密钥空间大、敏感性高，能有效地抵抗穷举分析、差分分析和统计分析。

Image encryption algorithm based on complex chaotic sequences

For the low dimensional chaotic system, the key space is small and the security of the encryption system is low. This paper presented an image encryption method for complex chaotic sequences formed by sine chaos changing uniformly distributed logistic chaos order. First, it generated a logistic chaotic sequence obeying uniform distribution, and used sine chaotic sequence to rearrange the repeated part after the integer of the sequence, so that it used the compound chaotic sequence without repeating value for pixel position disorder. After that, because position scrambling alone could change the histogram features of gray statistics of the image, it used sine chaos to rearrange the entire logistic chaos sequence to form compound chaotic sequence, so as to complete image encryption by pixel diffusion. It measured the method security from key space, key sensiti-vity, differential analysis, statistical histogram, adjacent pixel correlation and information entropy. The experimental results show that this method has a large key space and high sensitivity, and can effectively resist exhaustive analysis, differential analysis and statistical analysis.