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Florian Alt, Stefan Schneegass, Alireza Sahami, Mariam Hassib, Andreas Bulling
Graphical Passwords in the Wild - Understanding How Users Choose Pictures and Passwords in Image-based Authentication Schemes
In MobileHCI '15: Proceedings of the 17th International Conference on Human-Computer Interaction with Mobile Devices and Services. Copenhagen, Denmark, August 24 - 27, 2015. ACM, New York, NY, USA. (bib)

Common user authentication methods on smartphones, such as lock patterns, PINs, or passwords, impose a trade-off between security and password memorability. Image-based passwords were proposed as a secure and usable alternative. As of today, however, it remains unclear how such schemes are used in the wild. We present the first study to investigate how image-based passwords are used over long periods of time in the real world. Our analyses are based on data from 2318 unique devices collected over more than one year using a custom application released in the Android Play store. We present an in-depth analysis of what kind of images users select, how they define their passwords, and how secure these passwords are. Our findings provide valuable insights into real-world use of image-based passwords and inform the design of future graphical authentication schemes.