PushID: A Pressure Control Interaction-Based Behavioral Biometric Authentication System forSmartwatches

Abstract

Smartwatches support a wide range of functionality, including mediating access to sensitive data and services. However, securing access to them is difficult due to their small size—it is difficult, for example, to enter alphanumeric passwords accurately due to the limited space available to present a keyboard. Consequently, 4-digit PIN is commonly used to secure smartwatches, a technique widely acknowledged to be highly vulnerable to simple guessing attacks. To address these usability and security issues, we propose PushID, a new behavioral biometric technique for a smartwatch that combines four on-screen targets with five pressure levels to enable input of any one of 20 unique symbols from a single screen touch. In addition to this relatively large input space, PushID captures behavioral features during pressure input (e.g., finger touch profile, wrist motions) and uses this as a behavioral biometric. We report on a preliminary study of PushID and its security against random guessing attack: it achieves good usability for a single input (approximately 2 s) and high resistance to guessing (false-positive rates of 1.05%). We argue that pressure-based input can improve the security and maintain the usability of smartwatch lock systems. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.