摘要：提出一种基于物理层安全的安全保密电话的实现方法。该方法通过在双向通信的每个信道上释放人工噪声，使得线路任意窃听点检测到的信号功率远低于噪声功率，从而无法识别通信信息。合法用户采用同频同时全双工技术消除人工噪声，恢复正常通信。理论分析与实验结果表明，该系统能有效抑制自干扰，使合法用户的信干噪比显著优于窃听者。硬件原型的成功研制验证了系统的实用性和有效性，为高安全性通信场景提供了可行的技术解决方案。

关键词：物理层安全；同频同时全双工；保密电话；人工噪声

Abstract: An implementation method for a secure telephone system based on physical layer security is proposed. The security principle involves injecting artificial noise into each bidirectional communication channel, ensuring that the signal power detected by any illegal eavesdropper at any probing point on the line is far lower than the artificial noise power, thereby preventing information extraction.  Legitimate users employ co-frequency co-time full-duplex technology to cancel the artificial noise and recover the original communication signal. Theoretical analysis and experimental results demonstrate that this system can effectively eliminate self-interference, allowing the legitimate user's signal-to-interference-plus-noise ratio to significantly outperform that of an eavesdropper, thereby ensuring communication security. The successful implementation of a hardware prototype further validates the system's practicality and effectiveness, offering a feasible technical solution for high-security communication scenarios.

Keywords: physical layer security; co-frequency co-time full-duplex; secure telephone; artificial noise