Anti-Spoofing Facial Authentication Based on COTS RFID.

Current facial authentication (FA) systems are mostly based on the images of human faces, thus suffering from privacy leakage and spoofing attacks. Mainstream systems utilize facial geometry features for spoofing mitigation, but they are still vulnerable to feature manipulation, e.g. , 3D-printed human faces. In this paper, we propose a novel privacy-preserving anti-spoofing FA system, named RFace, which extracts both the 3D geometry and inner biomaterial features of faces using a COTS RFID tag array. These features are difficult to obtain and forge, hence are resistant to spoofing attacks. Unlike images, RF signals are not perceptible to human eyes, so RFace protects user's privacy. We build a theoretical model to rigorously prove the feasibility of feature acquisition and the correlation between facial features and RF signals. To enhance the security of RFace, we specify the tag reading order for each authentication to defend against the signal replay attack. For practicality, we design an effective algorithm to mitigate the impact of unstable distance and angle deflection from the face to the array. Extensive experiments with 30 participants and three types of spoofing attacks show that RFace achieves an average authentication success rate of over 95.7 $\%$ and an EER of 4.4 $\%$ . More importantly, no replay attack or spoofing attack succeeds in deceiving RFace in the experiments.