Li Qi, Meng Xiangfeng, Yin Yongkai, Wu Huazheng
School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Qingdao 266237, China.
Sensors (Basel). 2021 Sep 15;21(18):6178. doi: 10.3390/s21186178.
Multi-image encryption technology is a vital branch of optical encryption technology. The traditional encryption method can only encrypt a small number of images, which greatly restricts its application in practice. In this paper, a new multi-image encryption method based on sinusoidal stripe coding frequency multiplexing and deep learning is proposed to realize the encryption of a greater number of images. In the process of encryption, several images are grouped, and each image in each group is first encoded with a random matrix and then modulated with a specific sinusoidal stripe; therefore, the dominant frequency of each group of images can be separated in the Fourier frequency domain. Each group is superimposed and scrambled to generate the final ciphertext. In the process of decryption, deep learning is used to improve the quality of decrypted image and the decryption speed. Specifically, the obtained ciphertext can be sent into the trained neural network and then the plaintext image can be reconstructed directly. Experimental analysis shows that when 32 images are encrypted, the CC of the decrypted result can reach more than 0.99. The efficiency of the proposed encryption method is proved in terms of histogram analysis, adjacent pixels correlation analysis, anti-noise attack analysis and resistance to occlusion attacks analysis. The encryption method has the advantages of large amount of information, good robustness and fast decryption speed.
多图像加密技术是光学加密技术的一个重要分支。传统的加密方法只能加密少量图像，这在很大程度上限制了其在实际中的应用。本文提出了一种基于正弦条纹编码频率复用和深度学习的新型多图像加密方法，以实现对更多图像的加密。在加密过程中，将多幅图像进行分组，每组中的每幅图像首先用一个随机矩阵进行编码，然后用特定的正弦条纹进行调制；这样，每组图像的主频在傅里叶频域中就可以被分离出来。将每组图像进行叠加和置乱，生成最终的密文。在解密过程中，利用深度学习提高解密图像的质量和解密速度。具体来说，将得到的密文送入训练好的神经网络，然后直接重建明文图像。实验分析表明，当加密32幅图像时，解密结果的相关系数CC可达0.99以上。从直方图分析、相邻像素相关性分析、抗噪声攻击分析和抗遮挡攻击分析等方面验证了所提加密方法的有效性。该加密方法具有信息量大、鲁棒性好、解密速度快等优点。
