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Emanuel von Zezschwitz, Paul Dunphy, Alexander De Luca
Patterns in the Wild: A Field Study of the Usability of Pattern and PIN-based Authentication on Smartphones
In MobileHCI '13: Proceedings of the 15th international conference on Human-computer interaction with mobile devices and services. ACM, New York, NY, USA, 261-270. ISBN 978-1-4503-2273-7. (bib)

Graphical password systems based upon the recall and reproduction of visual patterns (e.g. as seen on the Google Android platform), are assumed to have desirable usability and memorability properties. However, there are no empirical studies that explore whether this is actually the case on an everyday basis. In this paper, we present the results of a real world user study across 21 days that was conducted to gather such insight. We compared the performance of Android-like patterns in comparison with standard PIN, both on smartphones, under realistic conditions. The results indicate that PIN outperforms the pattern lock when comparing input speed and error rates. However, the qualitative results suggest that users tend to accept this and are still in favour of the pattern lock to a certain extent. For instance, it was rated better in terms of ease-of-use, feedback and likeability. Most interestingly, even though the pattern lock does not provide any undo or cancel functionality, it was rated significantly better than PIN in terms of error recovery; this provides interesting insight into the relationship between error prevention and error recovery in user authentication.