Study On Encryption With Computer Generated Hologram

Along with the rapid development of the informatization of human society, the information security is becoming more and more important. However, the information published and transmitted on the Internet is convenient and quick meanwhile faced with potentially dangerous that damaged by the lawbreakers. In particular, some information that related to the vital interests of the individual, collective and state. To meet such a severe challenge, people have proposed a variety of encryption techniques successively. It mainly includes computer encryption, quantum encryption and optical encryption. As a special encryption method, encryption with holographic technique can be achieved with computer or optical method, and is widely used in information security fields. The computer has a very strong flexibility in processing data. Some excess items produced by optical holography can be artificially removed with computer-generated hologram (CGH) and then we can reconstruct a new holographic function. The other hand, since the theory of optical encryption information can be hided in many parameters, such as phase, frequency, polarization or wavelength, etc. It makes the optical encryption systems having excellent coding capacity, which is showing a high security. In addition, since the1980s, owing to the chaotic system has many good properties, such as the random phase array constructed by a chaotic sequence of the non-linear deterministic system has good class randomness, extremely sensitivity to initial conditions and good confidentiality, the idea of using chaotic systems to design new ciphers has attracted more and more researchers attention.This paper presents an overview of optical encryption technology in information security fields, and then summarizes typical encryption methods appeared so far. The following is analysis of CGH theory and a series of easy method based on (CGH), In-depth study, a series of method based on chaotic sequence random phase encoding encryption technology is introduced. Considering the practical application and making use of their respective advantages, the encryption scheme for different types of information is proposed based on the two theories. In this paper, the content and structure arrangements as follows:In the first part, a brief review of optical encryption technology is presented, and the principle of some typical optical encryption techniques to achieve encryption is also discussed.In the second part, the basic theory and coding principle of CGH is presented firstly, as well as the basic procedure of CGH applied in encryption. An introduction to chaos theory is also given, meanwhile including the analysis of existing encryption technology respectively.In the third part, gray-scale image encryption and decryption technique is proposed, combined chaotic sequence random phase encoding technology and CGH in the Fresnel domain. And then it gives analysis of the principle with this technique and simulation.In the forth part, color image encryption and decryption is proposed, combined chaotic sequence random phase encoding technology and CGH in the Fresnel domain. And then it gives analysis of the principle with this technique and simulation.In the fifth part,3-D Objects encryption and decryption is proposed, combined chaotic sequence random phase encoding technology and CGH in the Fresnel domain. And then it gives analysis of the principle with this technique and simulation.