Image encryption scheme based on computer generated holography and time-averaged moire

A technique of computational image encryption and optical decryption based on computer generated holography and time-averaged moire is investigated in this paper. Dynamic visual cryptography (a visual cryptography scheme based on time-averaging geometric moire), Gerchberg-Saxtonalgorithm and 3D microstructure manufacturing techniques are used to construct the optical scheme. The secret is embedded into a cover image by using a stochastic moire grating and can be visually decoded by a naked eye. The secret is revealed if the amplitude of harmonic oscillations in the Fourier plane corresponds to an accurately preselected value. The process of the production of 3D microstructure is described in details. Computer generated holography is used in the design step and electron beam lithography is exploited for physical 3D patterning. The phase data of a complex 3D microstructure is obtained by Gerchberg-Saxton algorithm and is used to produce a computer generated hologram. Physical implementation of microstructure is performed by using a single layer polymethyl methacrylate as a basis for 3D microstructure. Numerical simulations demonstrate efficient applicability of this technique.