Optical double-image cryptosystem based on interference principle and spatial encoding

We propose a novel optical double-image encryption and decryption method by integrating a cryptosystem based on the optical interference principle with a spatial encoding technique. This proposed integration overcomes the silhouette problem of the discloser of input image information; thus, it increases the security level of the overall process. Not only the security is increased but also the capacity for signal hiding is fulfilled for cryptosystems based on interference. In this work, the two Angio retina images, which are very effective for verification purposes, are considered as input images to validate the authorization of the two biometric users. An attack analysis is performed to check the robustness of the proposed cryptosystem. The performance and effectiveness of the system are verified by numerical simulations.