The Research Of Cross-Layer Security Based On OCDMA And Encryption Algorithm

Optical code division multiplexing access(OCDMA)is considered as one of the attractive access technologies in both military and civil applications due to its advantages such as high capacity,simple networking protocol,and the potential of security enhancement for the physical layer.Usually,people regarded the security as an inherent characteristic of the OCDMA and the OCDMA system should have excellent security performance.But the current researches show the incipient faults of security are existed in the OCDMA system.Besides,with the development of the computer technology,many encryption algorithms,which were thought to be security,were creaked in succession,such as Data Encryption Standard(DES),RSA algorithm.The fact proved that both the OCDMA system and encryption algorithm can offer limited single layer security,and if improve their security separately,they will be limited by other kinds of factors in the meantime.However,if we can combine the security advantages of them,these security problems can be solved.Therefore,this paper proposes the scheme of cross-layer communication system based on the OCDMA and encryption algorithm,and quantitatively analyzes its security for the first time.This project was supported by NSFC “Research on physical layer security and optical coding for free space optical communication(61671306)”,and JCYJ “Research on key technologies of optical communication based on optical encoding physical layer security(20160328145357990)”.The main work of this paper is as follows:1)The scheme of cross-layer communication system based on the OCDMA and encryption algorithm is proposed in this paper.The physical layer of this system adopted incoherent one-dimensional temporal encoded OCDMA system and AES is applied on the data layer.This paper firstly proposes a method for quantitatively analyzing the security of the cross-layer communication system.This method can quantitatively analyze the influences on the system security caused by the signal to noise ratio of eavesdropper,the code type,system users,synchronous and asynchronous,code interception time,cryptanalysis time.Then,the models of cross-layer communication system in single user and multi-user conditions are built by using Optisystem and Matlab.The simulation result displays that only in the situation of matching code decoding and correct key decryption,the system is able to recover the source information.2)The scheme of cross-layer communication system based on the two-dimensional reconfigurable OCDMA and encryption algorithm is proposed in this paper.It uses the two-dimensional reconfigurable codec based on the wavelength selective switch(WSS),and the supercontinuum source,which supports the dynamic code reconfiguration of the WSS and offers 76 wavelength options in maximum.The error free coding transmission experiment is succeeded in this paper.Later,this paper quantitatively analyzes the security of this cross-layer communication system,and the result demonstrated that reconfigurable code is able to strengthen the security of the system and greatly enhance the difficulty for code interception.Finally,according to the reconfiguration of the code and the transformability of the encryption algorithm,this paper researches the feasibility of further combining security and enhancing efficiency of the cross-layer communication system,and analyzes the security of the system.