基于长度可变密钥的光学图像加密方法  

Optical image encryption method based on variable length key

作　　者：杨晓云[1] 石峰[1] YANG Xiaoyun;SHI Feng(Taiyuan University,Taiyuan 030001 China)

机构地区：[1]太原学院,太原030001

出　　处：《激光杂志》2024年第2期107-112,共6页Laser Journal

基　　金：山西省高等学校改革创新项目(No.J2020380);山西省教育科学“十三五”规划项目(No.GH-19136)。

摘　　要：为提升光学图像加密效果,设计了一种基于长度可变密钥的光学图像加密方法。基于混沌方程构成混沌序列均匀化普适算法,运用该算法生成均匀化伪随机序列,以此作为长度可变密钥,经空间光调制器调制后,转换此类密钥为伪随机相位掩模(PRPM),运用两个转换后PRPM双重随机相位编码初始光学图像,并结合变形分数傅里叶变换(AFrFT),相位转换编码后光学图像,获得加密光学图像,完成光学图像加密。实验结果显示,该方法可针对不同光学图像生成敏感性与唯一性密钥,实现不同光学图像的加密处理,加密效果显著,加密光学图像的像素频数分布均匀,且解密后光学图像与初始光学图像几乎一致,整体加解密效果理想,可有效保障光学图像的安全性,而且本方法可以在最短3 s的时间内完成光学图像的加密和解密,加解密效率更高,综合效果更佳。In order to improve the effect of optical image encryption,this paper designs an optical image encryption method based on variable length key.Based on the chaos equation,a universal algorithm for homogenization of chaotic sequences is constructed.The algorithm is used to generate homogenized pseudo-random sequences,which are used as variable-length keys.After being modulated by a spatial light modulator,these keys are converted into pseudo-random phase masks(PRPM).Two converted PRPM double random phases are used to encode the initial optical image,and combined with the deformed fractional Fourier transform(AFrFT),the optical image after phase conversion is encoded,Obtain encrypted optical image and complete optical image encryption.The experimental results show that this method can generate sensitive and unique keys for different optical images,and realize the encryption of different optical images.The encryption effect is significant,the pixel frequency distribution of the encrypted optical image is uniform,and the decrypted optical image is almost the same as the original optical image.The overall encryption and decryption effect is ideal,which can effectively guarantee the security of the optical image,Moreover,the method in this paper can complete the encryption and decryption of optical images in the shortest time of 3s.The encryption and decryption efficiency is higher and the comprehensive effect is better.

关 键 词：长度可变密钥 光学图像加密 混沌序列 相位掩模 随机相位编码 傅里叶变换 

分 类 号：TN241[电子电信—物理电子学]