On the Usefulness of User Nudging and Strength Indication Concerning Unlock Pattern Security

Abstract

Strong passwords rely on complexity and length, no matter if text-based or of any other type. For text-based passwords, there are many established methods to measure complexity while for graphical passwords, e.g., unlock patterns on mobile devices, it is still an open question what criteria can be used to describe complexity. Also, users tend to choose a stronger password if the strength of their password is visualized. We conduct a user study on the helpfulness of strength indication and user nudging regarding unlock patterns. Participants create such graphical passwords under carefully specified circumstances, e.g., practical nudges on how to improve their password's security. We show that the choice of a strong password does not rely on being tech-savvy and users with different technical backgrounds can be helped by visualizations of a graphical password strength as well as by hints on how to improve it. Most users even perceive this as a helpful feature.