Communicating Device Confidence Level and Upcoming Re-Authentications in Continuous Authentication Systems on Mobile Devices

Authors: 

Lukas Mecke, University of Applied Sciences Munich, Munich, Germany and LMU Munich, Munich, Germany; Sarah Delgado Rodriguez and Daniel Buschek, LMU Munich, Munich, Germany; Sarah Prange, University of Applied Sciences Munich, Munich, Germany and Bundeswehr University Munich, Munich, Germany and LMU Munich, Munich, Germany; Florian Alt, Bundeswehr University Munich, Munich, Germany

Abstract: 

Continuous implicit authentication mechanisms verify users over time. In case the device's confidence level (DCL) is too low, the user is prompted with a re-authentication request, which has been shown to annoy many users due to its unpredictable nature. We address this with a novel approach to enable users to anticipate the need for re-authentication with two indicators: (1) a long term indicator shows the current DCL and its development over time, and (2) a short term indicator announces that re\hyp authentication is imminent. In both cases voluntary re-authentication allows the DCL to be raised and a device lock to be avoided. We tested the indicators in a four week field study (N=32). Our results show that both indicators were preferred over giving no indication and that importance and sensitivity of the interrupted task have a strong impact on user annoyance. Voluntary re-authentications were perceived as positive.

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BibTeX
@inproceedings {238299,
author = {Lukas Mecke and Sarah Delgado Rodriguez and Daniel Buschek and Sarah Prange and Florian Alt},
title = {Communicating Device Confidence Level and Upcoming Re-Authentications in Continuous Authentication Systems on Mobile Devices},
booktitle = {Fifteenth Symposium on Usable Privacy and Security ({SOUPS} 2019)},
year = {2019},
address = {Santa Clara, CA},
url = {https://www.usenix.org/conference/soups2019/presentation/mecke-confidence},
publisher = {{USENIX} Association},
month = aug,
}