CaphandAuth: Robust and Anti-spoofing Hand Authentication via COTS Capacitive Touchscreens

Utilizing unique physiological or behavioral traits, biometrics offers an intuitive authentication approach. However, common biometric modalities are susceptible to ambient factors and privacy concerns. This paper proposes CaphandAuth, a novel capacitive touchscreen-based hand authentication system. Using intrinsic capacitive imaging within the touchscreen, it provides a new secure, cost-effective, and user-friendly biometric authentication solution that is inherently resilient to environmental factors. To this end, CaphandAuth captures consecutive capacitive frames as the hand moves across the touchscreen. These frames are processed with an innovative super-resolution algorithm tailored for deformable objects to enhance details. A learning-based feature extractor then derives expressive and adaptive feature representations from the enhanced images. Extensive experiments demonstrate that CaphandAuth achieves an authentication accuracy of 99.84% and an equal error rate (EER) of 2.77% on a commercial tablet. Moreover, Caphand-Auth exhibits formidable resilience to diverse deceiving attempts, including handprint simulation attacks, counterfeit spoofing attacks, and puppet attacks, making it a robust and secure solution in real-world scenarios.