Multi-touch authentication on tabletops

Abstract

The introduction of tabletop interfaces has given rise to the need for the development of secure and usable authentication techniques that are appropriate for the co-located collaborative settings for which they have been designed. Most commonly, user authentication is based on something you know, but this is a particular problem for tabletop interfaces, as they are particularly vulnerable to shoulder surfing given their remit to foster co-located collaboration. In other words, tabletop users would typically authenticate in full view of a number of observers. In this paper, we introduce and evaluate a number of novel tabletop authentication schemes that exploit the features of multi-touch interaction in order to inhibit shoulder surfing. In our pilot work with users, and in our formal user-evaluation, one authentication scheme - Pressure-Grid - stood out, significantly enhancing shoulder surfing resistance when participants used it to enter both PINs and graphical passwords.