Han Qing, Zhao Wenjing, Zhai Aiping, Wang Zhirun, Wang Dong
Opt Express. 2020 Nov 23;28(24):36432-36444. doi: 10.1364/OE.411327.
Scattering media are generally regarded as an obstacle in optical imaging. However, the scattering of a diffuser can be exactly taken as an advantage to act as random phase masks in the field of optical encryption to enhance information security. Here, we propose and demonstrate a dynamic diffuser based optical encryption method, which increases the ciphering strength by exploiting the uncorrelated characteristics of the dynamic diffuser as well as randomly sampling the plaintext multiple times. The light emitted from a randomly sampled plaintext passing through the dynamic diffuser generates noise-like speckles, and then SNR of the recorded speckles is further reduced for obtaining the ciphertexts, which makes COA using PRA almost impossible. The specific uncorrelated characteristics of the dynamic diffuser make the ciphertexts and the PSF keys of the optical encryption unique. Therefore, only authorized users who mastered the keys can decrypt the plaintext. The proposed method is very simple and flexible since it can also achieve the encryption offline by performing convolutions on partial-plaintexts with pre-recorded uncorrelated PSFs to generate speckle patterns and then reducing their SNR to obtain the ciphertexts. This type of encryption technique has a promising prospect in applications involving images and/or videos information encryption owing to its simplicity and flexibility.
散射介质通常被视为光学成像中的一个障碍。然而，在光学加密领域，漫射器的散射可被确切地用作一种优势，充当随机相位掩膜以增强信息安全性。在此，我们提出并演示了一种基于动态漫射器的光学加密方法，该方法通过利用动态漫射器的不相关特性以及对明文进行多次随机采样来提高加密强度。从随机采样的明文发出并通过动态漫射器的光会产生类似噪声的散斑，然后为了获得密文，记录的散斑的信噪比会进一步降低，这使得使用PRA的COA几乎不可能实现。动态漫射器的特定不相关特性使得光学加密的密文和PSF密钥具有唯一性。因此，只有掌握密钥的授权用户才能解密明文。所提出的方法非常简单且灵活，因为它还可以通过对部分明文与预先记录的不相关PSF进行卷积以生成散斑图案，然后降低其信噪比来获得密文，从而实现离线加密。由于其简单性和灵活性，这种加密技术在涉及图像和/或视频信息加密的应用中具有广阔的前景。
