Multiple Image Encryption System Based on Nematic Liquid Photonic Crystal Layers

A novel design for multiple symmetric image encryption system based on a phase encoding is presented. The proposed encryptor utilizes a photonic bandgap (PBG) block in order to ensure high reflectivity over a relatively wide frequency range of interest. Also, the proposed encryptor can be utilized to encrypt two images simultaneously through the use of two nematic liquid crystal (NLC) layers across the PBG block. The whole system has been simulated numerically using the rigorous finite difference time domain method. To describe the robustness of the encryption, a root mean square of error and the signal to noise ratio are calculated. The statistical analysis of the retrieved images shows that the proposed image encryption system provides an efficient and secure way for real time image encryption and transmission. In addition, as the proposed system offers a number of advantages over existing systems such as simple design, symmetry allowing integrated encryptor/decryptor system, ultra high bandwidth and encrypting two images at the same time, it can be suitably exploited in optical imaging system applications.