The Study Of Optical Image Encryption In Phase Space

With the rapid development of Internet applications, information security has been used deeply into many fields. While the information security is the premise of network working security, more and more business and individual users, as well as scientist have to think seriously about a serious problem: How to effectively protect our information when many kinds of security threats appeared in the complex Internet society? How to manage to think about some innovation points based on the existing information security technology, so as to deal with all kinds of existing security attacks effectively? Therefore, the information security technology nowadays has become a research subjects with high attention.At present, the research of information security mainly includes traditional technology that base on the computer or electronic security system and the new information security technology such as quantum cryptography, biometrics, and optical information security technology. Compared with the traditional information security technology, optical information security technology has lots of characteristics such as high processing speed, high parallel speed and high encrypted dimension. It can also operate convolution and correlation quickly. However the linear relationship between the plaintext and cyphertext is one of the most critical security issues encountered in double random phase encryption(DRPE) technique. In this paper, we propose a phase-space optical technique by using the bilinear property of Ambiguity Function(AF), the main reseach work is as follows:First of all, we analyzed the encryption technique and decryption measures of several traditional optical encryption systems that based on DRPE. And a computer simulation was carried out about these systems. Through the theoretical analysis and simulation lots of danger was appeared which was hidden in the traditional optical encryption technology.Secondly, we proposed a phase-space optical technique in view of drawbacks of current linear optical encryption systems by using the bilinear property of AF. It focus on the property of AF, the reconstruction of the signal and the method of phase-space optical encryption. In addition, we made a cipher analysis of the noise interference to this research, and did some computer simulations.Finally, the safety analysis of optical encryption system in phase space was discussed. It made a signal simulation of the analysis by using the new phase recovery technique we proposed base on the Gerchberg-Saxton(GS) algorithm.