Information authentication system using interference of two beams in gyrator transform domain.

A novel information authentication system, i.e., an asymmetric optical interference of two beams in the gyrator transform (GT) domain, is proposed. In this algorithm, the input color image is divided into R, G, and B channels. The complex field of each channel is constructed by the inverse Fourier transform of the channel attached with a random phase function. The phase-only mask (POM) and amplitude-only mask (AOM) are analytically derived from the complex field. The POM and AOM are separately gyrator transformed. The two asymmetric phase keys and two encrypted images are obtained by the amplitude truncations and phase truncations of the transform images, respectively. Finally, the encoded image is produced by the interference of two encrypted images. The two asymmetric keys and two angle parameters of the GT are regarded as additional keys for each channel to enhance the security level of the cryptosystem. The noniterative authentication procedure is devoid of any silhouette problem. The proposed system can be implemented digitally or optically, and its architecture is free from optical misalignment problems. The theoretical analysis and numerical simulation results both validate the proposed technique.