The security of wireless challenge-response Physical Layer Authentication (PLA) based on Orthogonal Frequency Division Multiplexing (OFDM) relies on a sufficiently random fading channel condition, which is commonly assumed in existing studies. However, in practical scenarios, such a condition is not always guaranteed and the responses of OFDM subchannels may exhibit correlation.} Consequently, ensuring the security of such PLA systems remains an unsolved problem. In this paper, we propose a novel adversary model, called Maximum Differential Likelihood Generator (MDLG), which exploits the weak correlation property in practical wireless channel to launch effective attacks against PLA. Based on this model, we create a measurable guideline using randomness testing to decide when we can in fact use PLA in a practical wireless channel condition. Extensive real-world experiments validate the effectiveness of the MDLG attack and demonstrate how the proposed guideline can help protect the security of PLA.

翻译：基于正交频分复用（OFDM）的无线挑战-响应物理层认证（PLA）的安全性依赖于充分随机的衰落信道条件，这是现有研究中的普遍假设。然而在实际场景中，这种条件并非总能得到保证，OFDM子信道的响应可能表现出相关性。因此，这类PLA系统的安全性保障仍是一个未解难题。本文提出一种名为最大差分似然生成器（MDLG）的新型敌手模型，该模型利用实际无线信道中存在的弱相关特性对PLA发起有效攻击。基于此模型，我们通过随机性测试创建可测量指南，以判定在实际无线信道条件下何时可实际应用PLA。大量真实环境实验验证了MDLG攻击的有效性，并展示了所提指南如何协助保障PLA的安全性。