A Secure Asymmetric Optical Image Encryption Based on Phase Truncation and Singular Value Decomposition in Linear Canonical Transform Domain

A new asymmetric optical double image encryption algorithm is proposed, which combines phase truncation and singular value decomposition. *e plain text is encrypted with two-stage phase keys to obtain a uniformly distributed cipher text and two new decryption keys. *ese keys are generated during the encryption process and are different from encryption keys. It realizes asymmetric encryption and improves the security of the system. *e unscrambling keys in the encryption operation are mainly related to plain text. At the same time, the system is more resistant to selective plain text attacks; it also improves the sensitivity of decryption keys. With the application of phase truncation, the key space expanded and the security of the cryptographic system is enhanced. *e efficacy of the system is calculated by evaluating the estimated error between the input and retrieved images. *e proposed technique provides innumerable security keys and is robust against various potential attacks. Numerical simulations verify the effectiveness and security of the proposed technique.