Asymmetric Encryption Method in 4f System Based on Interference

An asymmetric encryption method in 4f system based on interference is proposed in this paper. The original image is transformed into two white stationary noise images, and the decryption keys are designed to be different from the encryption keys to realize asymmetric encryption. The decryption process is implemented in a 4f system of image addition with grating. This method has very high security as the asymmetric cryptosystem encryption system but also can be easy implemented in optical system. Besides, holographic plate or photorefractive crystal is not necessary in the encryption process. The simulation results prove the feasibility and security of this method.