Optical image encryption based on dyadic phase permutation in Fourier domain

Dyadic displacements of an image can be regarded as a special type of permutations of its pixel address. This property can be used to encrypt an image without information loss, damage or addition. In this paper, we propose a new optical image encryption technique based on dyadic permutations and hologram interference. First, we adopt hologram interference to extract the phase of Fourier transform of an input image, and then the phase is processed through dyadic permutations of exclusive-OR (XOR) operations. The original image can be successfully recovered by using the inverse procedure.