Optical image encryption based on XOR operations

Abstract

Kwangwoon UniversityDepartment of Electronic Engineering447-1, Wolge-Dong, Nowon-GuSeoul 139-701South KoreaAbstract. We propose a new optical image encryption technique basedon exclusive-OR (XOR) operations for a security system that controls theentrance of authorized persons. The basic idea is that we convert agray-level image to eight bit planes for image encryption. We use theXOR operation that is commonly used such as the well-known encryp-tion method. The input image is encrypted by performing optical XORoperations with the key bit stream that are generated by digital encryp-tion algorithms. The gray level input image is converted to eight bitplanes, which are represented on a liquid crystal device (LCD). The keydata represented on different LCDs is reproduced to eight bit planes by alenslet array. The optical XOR operations between the key data and thebit planes are performed by the polarization encoding method. The re-sults of XOR operations, which are detected by a CCD camera, areconverted to an encrypted gray-level image and the image is used as aninput to the binary phase extraction joint transform correlator (BPEJTC)for comparison with reference images. We present some simulation re-sults that verify the proposed method.