Physical Biometric Spoofing of 3D Dynamic On-Air Signature

3D on-air signatures represent a novel behavioral biometric that is highly challenging to imitate, even from a distance. However, the emergence of robotic arms capable of mimicking human movements poses a potential security vulnerability. This paper examines the possibility of generating 3D fingertip movements with a robotic arm that accurately mimic a 3D on-air signature to circumvent a biometric system. The robotic arm controls trajectory and velocity to generate a human-like movement. Robotic-made signatures are then used to spoof a 3D on-air dynamic signature biometric system, which relies on a DTW verifier. Experiments demonstrate that robotic signatures can effectively bypass a verifier exclusively trained with real signatures, underscoring the importance of incorporating an additional security layer, such as a liveness detector, into these biometric schemes.