基于多混沌系统的双图像光学加密算法

为了扩展双图像光学加密算法的密钥空间,克服双随机相位加密系统中随机相位掩模作为密钥难于存储、传输和重构的问题,突破传统图像加密的研究思路,提出了一种基于多混沌系统的双图像加密算法,构造了光学加密系统。系统增加混沌系统参数作为密钥,利用混沌加密密钥空间大和图像置乱隐藏性好的特点,构建基于Logistic混沌映射的图像置乱算法,利用Kent混沌映射生成的伪随机序列构造出一对随机相位掩模,分别放置在分数傅里叶变换光学装置的两端,图像经加密系统变换后得到密文。数值仿真结果表明,算法的密钥敏感性极高,能够有效地对抗统计攻击,具有较高的安全性。

Double optical images encryption method based on chaotic systems

In order to extend the key space of double optical images encryption algorithm and overcome the drawbacks of traditional double random phase encryption system, such as practical difficulty in random phase mask storage, transportation and reconstruction, an encryption algorithm of double optical images based on multiple-chaos system is proposed and the optical encryption system is constructed.By combining Logistic and Kent chaotic maps, the system can obtain a larger key space than that using double random phase encryption method alone.Considering the difficulty of image scrambling in detecting without the help of the original image, a scrambling transformation is designed based on Logistic chaotic map.Kent chaotic map is used to generate a couple of random phase masks, which are placed at two ends of optical fractional Fourier transform device separately.The original images are encrypted.Through the experimental analysis, sensitivity analysis and gray level histogram analysis, the algorithm has high flexibility, security, confidentiality and good robustness in face of statistical attacks.