Frozen-Tag-Based Physical-Layer Authentication Against User Interference

TL;DR

This paper introduces a frozen-tag-based physical-layer authentication framework that improves security and robustness against user interference by using polar code concepts to conceal raw tags.

Contribution

It proposes a novel frozen-tag scheme based on polar codes, enhancing authentication performance and security against adversaries.

Findings

Improved authentication accuracy under user interference.

Enhanced security by concealing raw tags from illegitimate receivers.

Theoretical and simulation results confirm robustness and security benefits.

Abstract

Tag-based physical layer authentication (PLA) has garnered significant attention due to its low complexity and enhanced security. However, existing PLA schemes encounter two challenges. First, unintended user interference, which overlaps with the authentication signal, corrupts the tag and degrades authentication performance. Second, the vulnerability introduced by direct embedding of the raw tag exposes the tag to the adversary and degrades the security. To address these challenges, this paper proposes a novel frozen-tag-based PLA framework. Different from typical schemes that directly embed the uncoded tag into the signal, a well-designed frozen tag is inserted for authentication, where the frozen tag is generated based on the concept of polar codes with the anchor information as information bits and raw tags as frozen bits. Accordingly, the proposed PLA framework offers two principal advantages. First, the authentication performance is improved since the legitimate receiver can decode the frozen tag and mitigate unintended user interference. Second, the authentication process becomes indecipherable to the illegitimate receiver due to the concealment of the raw tags. Furthermore, we conduct a comprehensive analysis of the proposed framework in terms of robustness, security, and compatibility. Theoretical analysis and simulation demonstrate that the proposed frozen-tag-based PLA framework not only enhances the detection performance but also significantly degrades Eve's capability to estimate the raw tags.