Replay-resilient Physical-layer Authentication for Battery-free IoT Devices

On battery-free IoT devices such as passive RFID tags, it is extremely difficult, if not impossible, to run cryptographic algorithms. Hence physical-layer identification methods are proposed to validate the authenticity of passive tags. However no existing physical-layer authentication method of RFID tags that can defend against the signal replay attack. This paper presents Hu-Fu, a new direction and the first solution of physical layer authentication that is resilient to the signal replay attack, based on the fact of inductive coupling of two adjacent tags. We present the theoretical model and system workflow. Experiments based on our implementation using commodity devices show that Hu-Fu is effective for physical-layer authentication.