Phase-only asymmetric encryption based on coherent superposition and phase-truncated Fourier transforms

A phase-only asymmetric encryption (POAE) based on coherent superposition and phase-truncated Fourier transforms is proposed in this paper. An original image can be encrypted into a phase-only mask (POM) by using a random phase mask. Thereafter, the POM is encrypted into an amplitude image via a series of asymmetric operations based on phase-truncated Fourier transforms. Finally, the encrypted result is hidden in a public image. The encryption can be performed digitally, and the decryption can be performed optically or digitally. Simulation results are presented to demonstrate the validity and security of the proposed protocol.