关键词: Gold码

Abstract: From the viewpoint of information-theoretical security, it’s the first time to analyze the physical-layer security of coherent time-spreading optical code division multiple access systems (OCDMA) by using secrecy capacity. The relationships between the secrecy capacity and the system parameters are discussed for coherent time-spreading OCDMA systems. The wiretap channel model of OCDMA systems is firstly established and the secrecy capacity of OCDMA systems is calculated. Then, using Gold codes as an example, the impacts of the key system parameters (user number N, input optical power P and code length N) on the security of coherent time-spreading OCDMA systems are evaluated. The results indicate that the coherent time-spreading OCDMA systems have great physical-layer security against fiber tapping attacks and the above key system parameters have important influences on improving the physical-layer security of coherent time-spreading OCDMA systems. Therefore, the security of coherent time-spreading OCDMA systems can be improved by choosing the appropriate parameter values.

Key words: Gold codes