When to Use Wireless Challenge-Response Physical Layer Authentication: Design of a Measurable Guideline for OFDM

TL;DR

This paper develops a measurable guideline for when wireless OFDM-based challenge-response physical layer authentication is secure, based on channel randomness testing, supported by real-world experiments.

Contribution

It introduces the MDLG adversary model and a practical guideline to determine the suitability of PLA in real wireless channels.

Findings

MDLG effectively attacks OFDM PLA in correlated channels.

The guideline accurately predicts secure conditions for PLA.

Real-world experiments validate the attack and the guideline's effectiveness.

Abstract

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.