CipherCard: Enhancing Security on Common Touchscreen Devices using Two-factor Authentication

Abstract

We present CipherCard, a physical token that defends against shoulder-surfing attacks on user authentication on touchscreen devices. Placed over a touchscreen pin-pad, CipherCard remaps a user’s touch points on the physical token to different locations on the pin-pad (i.e. as a substitution cipher). It translates a visible user password into a different system password received by a touchscreen, hiding the system password from observers. CipherCard enhances authentication security through Two-Factor Authentication (TFA), in that both the correct user password and a specific card are needed for authentication. We explore the design space of CipherCard, and describe three implemented variations each with unique capabilities. Based on user feedback, we discuss the security and usability implications of CipherCard, and describe several avenues for continued exploration.