SnapApp is a novel unlock concept for mobile devices that reduces authentication overhead with a time-constrained quick-access option. SnapApp provides two unlock methods at once: While PIN entry enables full access to the device, users can also bypass authentication with a short sliding gesture (“Snap ”). This grants access for a limited amount of time (e.g. 30 seconds). The device then automatically locks itself upon expiration. Our concept further explores limiting the possible number of Snaps in a row, and configuring blacklists for app use during short access (e.g. to exclude banking apps). In the paper we discuss opportunities and challenges of this concept based on a 30-day field study with 18 participants, including data logging and experience sampling methods. Snaps significantly reduced unlock times, and our app was perceived to offer a good tradeoff. Conceptual challenges include, for example, supporting users in configuring their blacklists.


buschek2016chi1.jpg Daniel Buschek, Fabian Hartmann, Emanuel von Zezschwitz, Alexander De Luca und Florian Alt. SnapApp: Reducing Authentication Overhead with a Time-Constrained Fast Unlock Option. In Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems. CHI '16. ACM, New York, NY, USA. [Download Bibtex]