Fig. 1: Conceptional diagram of the proposed optical encryption system.
From: High-security learning-based optical encryption assisted by disordered metasurface
a Optical encryption. The sender (Alice) illuminates light beams with two different polarizations of P(i) and P(j) onto the phase profiles of the superposition of plaintexts (human face images) and security keys (QR codes), which propagates through DM, generating ciphertexts (speckles). b Learning-based decryption. Two deep neural networks (DNN) of the same structure, e.g., P(i)-DMNet and P(j)-DMNet, are trained with data obtained with incident beams of P(i) and P(j), respectively. After recording the ciphertext and being authorized by Alice to acquire the security key and the polarization of the incident beam, the receiver (Bob) can feed the ciphertext and the security key into the corresponding neural network to decrypt the plaintext. The mark “×” above the straight line with arrows at both ends indicates that the information cannot be commutative. DM disordered metasurface.
