Optical double phase encoding improvement using Fourier plane modulation

Double phase encoding suffers from vulnerability to attacks such that brute force attacks and chosen plain text attacks. A method to improve the security of double phase encoding against those attacks is presented. The proposed method suggests placing an intensity image at the Fourier plane. This added Fourier plane modulation prevents an attacker from recovering the Fourier plane encryption phase mask. The inverse of the encryption image is used to retrieve the original image. Results show that the proposed modification improves the immunity of double phase encoding against plain text and brute force attacks.