Secure Spread Spectrum Communication Using Super-Orthogonal Optical Chaos Signals

This paper proposes an analog spread spectrum secure communication system by designing a super-orthogonal two-dimensional electro-optic time delayed chaotic system. Two negatively correlated (called “super-orthogonal”) broadband optical chaotic signals can be generated. According to the binary symbol to be transmitted, the two signals are coupled into channel in turn. Benefiting from the wide spectrum and super-orthogonal characteristics of the two optical chaotic signals, the scheme shows excellent anti-noise performance which is verified by numerical simulations. Moreover, by introducing the modulation signal time delay feedback, the security of the system can be improved. The system is capable of resisting time delay signature extraction and return map attack, which are inherent vulnerabilities of time-delayed chaotic system and chaotic shift keying mechanism.