基于联合变换相关器和矢量分解的图像加密方法

Image encryption based on joint transform correlator and vector decomposition

为了提高基于联合变换相关器(JTC)的加密方法的抗攻击能力,提出了一种基于JTC和矢量分解的图像加密方法。在加密过程中,通过计算机预处理,先将待加密图像进行了基于干涉原理的矢量分解,再利用基于JTC的光学加密系统进行图像加密并记录加密图像。解密时,通过其中一个密钥解密联合功率谱得到一幅纯相位图,再与另一个与明文相关的密钥进行相干叠加得到相应解密结果。本文加密系统易于实现,通过矢量分解增加了一个与明文相关的密钥,破坏了加密图像和原始图像间的线性关系,有效地提高了系统安全性。仿真实验结果和分析验证了本文加密方法的可行性和安全性。

To realize the optical image encryption system, which is based on joint transform correlator （JTC）, and achieve high robustness against attacks, an optical image encryption scheme based on JTC and vector decomposition is proposed in this paper. In the encryption process,vector operation, which is based on the optical interference principle, on the plaintext is carried out by computer preprocessing. Then, the image is encrypted by using the JTC-based optical image encryption system, and the joint pow- er spectrum is recorded as the encrypted image. For decryption,the cipher text is decrypted with one of the keys first. Then,the decrypted pure phase image and the other key which is directly related to the plaintext,are coherent with each other, achieving the original image. Compared with the classical JTC- based optical image encryption system,an extra key,which is related to plaintext,is used to enhance the security of the encryption system. The optical image encryption system is easy to realize. The plaintext related key is added to improve the security by vector decomposition which can remove the linearity be- tween the cipher text and the plaintext. Furthermore, several numerical simulation results and analysis are carried out to demonstrate the validity and security of the proposed scheme.