LiPass

Abstract

LiPass is a secure and contactless door access control system that combines mobile-based facial biometric authentication with Light Fidelity (Li-Fi) communication to address the security and privacy limitations of traditional access control methods. Facial embeddings are generated locally on the user's smartphone using TensorFlow Lite and the FaceNet model, while biometric verification is performed exclusively on the backend server. Biometric data is transmitted only during enrollment using secure HTTPS/TLS channels, encrypted with AES-128-GCM, and stored securely in the cloud. During authentication, biometric data is decrypted only in volatile memory and immediately erased after verification. LiPass employs a multi-factor authentication model based on user credentials, facial recognition, and a smartphone-based Li-Fi authentication signal. A short-lived authentication token is generated by the backend server, transmitted optically via the smartphone flashlight, and validated by a Raspberry Pi-based door unit to unlock the door. Experimental evaluation demonstrates reliable operation and an average authentication time of approximately five seconds.