Learning complex scattering media for optical encryption.

Optical encryption has provided a new insight for securing information; however, it is always desirable that high security can be achieved to withstand the attacks. In this Letter, we propose a new method via learning complex scattering media for optical encryption. After the recordings through complex scattering media, a designed learning model is trained. The proposed method uses an optical setup with complex scattering media to experimentally record the ciphertexts and uses a learning model to generate security keys. During the decryption, the trained learning model with its parameters is applied as security keys. In addition, various parameters, e.g., virtual phase-only masks, can be flexibly applied to further enlarge key space. It is experimentally demonstrated that the proposed learning-based encryption approach possesses high security. The proposed method could open up a new research perspective for optical encryption.