Voltage Profile-Driven Physical Layer Authentication for RIS-aided Backscattering Tag-to-Tag Networks

This paper proposes a novel physical layer authentication (PLA) scheme for backscattering tag-to-tag networks (BTTNs), where a Talker Tag (TT) communicates passively with a Listener Tag (LT) in the presence of a potential adversary. Designed for ultra-low power tags without cryptographic capability, the proposed PLA leverages the unique voltage profiles generated by the tags’ energy harvesting and demodulation circuits to form physical-layer signatures for authentication. In addition, to enhance the reliability of voltage measurements, especially under weak signal conditions inherent within BTTNs, an indoor reconfigurable intelligent surface (RIS) is integrated to improve the received signal quality at LT. The proposed approach maintains a high authentication success rate even as the distance between TT and LT increases. A detailed security analysis demonstrates strong resilience against impersonation, man-in-the-middle, relay, and replay attacks, as long as the RIS controller remains secure. This robustness stems from the adversary’s inability to recreate the exact voltage profiles at LT, due to the inherent location-specific channel characteristics and the RIS-assisted signal shaping that the attacker cannot replicate. Furthermore, the simulation results confirm the effectiveness of the proposed RIS-assisted PLA, showing significant gains in authentication performance and secrecy capacity across diverse deployment scenarios.