Optical image encryption with a bit-plane separation method in phase-shifting digital holography

Abstract

In this paper, we propose a method for optical image encryption based on fractional Fourier transform (FRFT) and Arnold transform (ART) in phase-shifting digital holography. An input image is first divided into eight bit planes, and each bit plane is encrypted based on double random-phase masks and FRFT. Complex amplitude for the object is retrieved by phase-shifting digital holography in the hologram plane. The real and imaginary parts of the retrieved complex amplitudes for the 0th-7th bit planes are further encrypted using ART algorithm. Numerical results are shown to demonstrate the feasibility and effectiveness of the proposed technique. The sensitivity of security parameters, such as function orders in FRFT and iteration number in ART method, is also analyzed.