Optical image encryption and authentication using phase-only computer-generated hologram

Optical and photonics techniques such as computer-generated holograms (CGHs) are suggested to be used in security applications. In this paper, we present an approach to generate an authenticable phase-only hologram (APOH) for steganographic optical image encryption with phase optimization. The phase hologram can be calculated by the proposed integrated two-stage optimization method where Fresnel domain optimized random phase (OARP) method and modified two-step iterative Fourier transform algorithm under phase constraints are involved. The computer-generated APOH can be respectively verified and decrypted with an authentication key (A-key) and a decryption key(D-key). Numerical and experiment results prove the validity and security of the proposed approach, which offers a new method of holographic encryption for optical images.