User-Generated Free-Form Gestures for Authentication: Security and Memorability
This work addresses the need for robust authentication methods on mobile devices, offering strategies for generating secure and memorable gestures, though it is incremental as it builds on existing gesture research by introducing new metrics.
The paper tackled the problem of evaluating security and memorability for free-form multitouch gestures in mobile authentication by collecting a dataset from 63 participants and developing a modified metric based on mutual information, finding that one-finger gestures had higher average mutual information and that signatures and angular shapes were best remembered.
This paper studies the security and memorability of free-form multitouch gestures for mobile authentication. Towards this end, we collected a dataset with a generate-test-retest paradigm where participants (N=63) generated free-form gestures, repeated them, and were later retested for memory. Half of the participants decided to generate one-finger gestures, and the other half generated multi-finger gestures. Although there has been recent work on template-based gestures, there are yet no metrics to analyze security of either template or free-form gestures. For example, entropy-based metrics used for text-based passwords are not suitable for capturing the security and memorability of free-form gestures. Hence, we modify a recently proposed metric for analyzing information capacity of continuous full-body movements for this purpose. Our metric computed estimated mutual information in repeated sets of gestures. Surprisingly, one-finger gestures had higher average mutual information. Gestures with many hard angles and turns had the highest mutual information. The best-remembered gestures included signatures and simple angular shapes. We also implemented a multitouch recognizer to evaluate the practicality of free-form gestures in a real authentication system and how they perform against shoulder surfing attacks. We conclude the paper with strategies for generating secure and memorable free-form gestures, which present a robust method for mobile authentication.