Bai Jiachen, Wang Hongxiang, Ji Yuefeng
Opt Express. 2021 Jan 18;29(2):706-718. doi: 10.1364/OE.413941.
A novel time-delay signature (TDS) concealing electro-optic (EO) chaotic system with multiply feedback nonlinear loops is proposed and analyzed by numerical simulation. The proposed system employs mutual injection structure implemented by two asymmetric branches named as multiply feedback nonlinear loop which introduces an extra nonlinear factor to the system dynamic equation. The complexity of the chaos system is increased by introducing this multiply feedback nonlinear loop. The permutation entropy (PE) of the proposed system is improved to higher than 0.96 when feedback strength (β) equals 5. The proposed system can enter to chaos regime with a small β (β = 0.8). The TDS is concealed effectively due to the extra nonlinear factor introduced by multiply feedback nonlinear loop. Meanwhile, key-space of the proposed system is about 10 times that of the classical EO system because more tunable time delay parameters are introduced. Furthermore, the performance of a secure communication system based on the proposed chaotic system is discussed, and the simulation results show that the system is sensitive to time delay parameters and robust to feedback strength, which proves the proposed system is suitable for secure communication.
提出了一种具有多重反馈非线性环路的新型时延签名（TDS）隐藏电光（EO）混沌系统，并通过数值模拟进行了分析。所提出的系统采用由两个不对称分支实现的互注入结构，这两个分支称为多重反馈非线性环路，它为系统动力学方程引入了一个额外的非线性因子。通过引入这种多重反馈非线性环路，增加了混沌系统的复杂性。当反馈强度（β）等于5时，所提出系统的排列熵（PE）提高到高于0.96。所提出的系统可以在较小的β（β = 0.8）下进入混沌状态。由于多重反馈非线性环路引入的额外非线性因子，TDS被有效地隐藏。同时，由于引入了更多可调时延参数，所提出系统的密钥空间约为经典EO系统的10倍。此外，还讨论了基于所提出混沌系统的安全通信系统的性能，仿真结果表明该系统对时延参数敏感，对反馈强度具有鲁棒性，这证明所提出的系统适用于安全通信。
