Asymmetric cryptosystem for securing multiple images using two beam interference phenomenon

• Multiple image encryption based on two beam interference principle is presented.
• Proposed scheme is compact and highly secure.
• The scheme resists the specific attack and is robust against occlusion attack.

In this paper, a novel optical encryption technique based on two beam interference principle and phase truncation approach is presented. The proposed scheme is compact, highly secure, and suitable for securing multiple images. Simulation results with three different images have been presented. The first two images to be encrypted are encoded into two parts. One is phase-only distribution and other is amplitude mask. The amplitude masks are preserved as decryption keys while phase distribution is used as encryption keys in order to encrypt the third image using phase-truncation approach. The proposed scheme offers higher level of security as it resists the specific attack on asymmetric cryptosystem and is robust against occlusion attack. Also, detailed study has been carried out employing keys which are dependent on and independent of the input image.