The Feet in Human-Centred Security: Investigating Foot-Based User Authentication for Public Displays

A large body of work investigated touch, mid-air, and gaze-based user authentication. However, little is known about authentication using other human body parts. In this paper, we investigate the idea of foot-based user authentication for public displays (e.g., ticket machines). We conducted a user study (N=13) on a virtual prototype, FeetAuth, on which participants use their dominant foot to rotate through PIN elements (0–9) that are augmented along a circular layout using augmented reality (AR) technology. We investigate FeetAuth in combination with three different layouts: Floor-based, Spatial, and Egocentric, finding that Floor-based FeetAuth resulted in the highest usability with 4-digit PIN entry as fast as M=6.71 (SD=0.67). Participants perceived foot-based authentication as socially acceptable and highlighted its accessibility. Our investigation of foot-based authentication paves the way for further studies on the use of the human body for user authentication.