Optical image encryption based on diffractive imaging

In this Letter, we propose a method for optical image encryption based on diffractive imaging. An optical multiple randomphasemask encoding systemis applied, and one of the phase-onlymasks is selected and laterally translated along a preset direction during the encryption process. For image decryption, a phase retrieval algorithm is proposed to extract a high-quality plaintext. The feasibility and effectiveness of the proposedmethod are demonstrated by numerical results. The proposed method can provide a new strategy instead of conventional interference methods, and it may open up a new research perspective for optical image encryption.