Integrated Optical Double Mask Encryption Systems

As the rapid development of computer technology and network communication technology, the pace of our life is speeding up. Information can be communicated convenient and frequent. Meanwhile, we are facing the threat of information being stolen, interference and destruction. Because of this hidden danger, the research of information encrypted technology has attracted a lot of attention. Compared with the traditional encryption system, the optical information processing system has many advantages, like: highly processing speed, multiple attribute, parallel processing. The optical encrypted technology has shown its unique charm and got a rapid development.We did a systematic research of the optical encrypted technology in this paper and briefly introduced the related theory, include:spatial filtering, Fraunhofer diffraction, Fresnel diffraction, the sampling and coding method of CGH. We study on the theory of double random phase encoding system in detail. As this method has some disadvantages and problems, we propose the corresponding method in three aspects:(1) Based on the classical double random phase encoding system, we introduce the amplitude mask on the spectrum plane of the4f system. The input image is joint encrypted by using phase mask and amplitude mask and can be multiple recorded in the same medium. We also present a new method of image hidden.(2) We handle the encrypted image by using CGH coding method. Because of the spread spectrum effect, the size information of input image has been hidden. We need the corresponding mask to decrypt according to different classes. So the system security is strengthened. In order to solve the linear problem in classic methods, we combine the Fourier transform with the Fresnel transform, which make a further improve of system security.(3) Breaking through the randomness of the mask, we use the orderly method gradually approaching the disorder and solve the problem of encryption mask plate which is difficult to duplicate. We design a experimental light path to realize the image encryption and decryption by using the reflection method. We also did the experimental research and analysis.