Pilot-Based Physical-Layer Authentication with High Covertness

This article concerns the problem of generating an appropriate tag for the covert Physical-Layer Authentication (PLA) schemes. This problem is important because an inappropriate tag introduces the following limitations: low covertness, low robustness, high complexity, and security vulnerabilities to active attacks. In this article, we compare the performance of two ways of generating an appropriate tag in prior covert schemes: message-based and pilot-based. Then, we propose an enhanced Pilot-based Covert (PC) scheme that not only effectively defends against replay attacks but also overcomes the limitations of prior covert schemes. Our experimental results show that the enhanced PC scheme has better covertness and robustness than both the Message-based Covert (MC) and PC schemes for defending against an impersonation attack. Moreover, both the enhanced PC and MC schemes have much better robustness than the PC scheme for defending against a replay attack but the enhanced PC scheme has a lower store requirement than the MC scheme.