To Have and Have Not: Variations on Secret Sharing to Model User Presence
UPSIDE - Workshop on Usable Privacy & Security for wearable and domestic ubIquitous DEvices
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Stafford-Fraser, Q., Stajano, F., Warrington, C., Jenkinson, G., Spencer, M., & Payne, J. (2014). To Have and Have Not: Variations on Secret Sharing to Model User Presence. UPSIDE - Workshop on Usable Privacy & Security for wearable and domestic ubIquitous DEvices, 1313-1320. https://doi.org/10.1145/2638728.2641705
We address the problem of locking and unlocking a device, such as a laptop, a phone or a security token, based on the absence or presence of the user. We detect user presence by sensing the proximity of a subset of their possessions, making the process automatic and effortless. As in previous work, a master key unlocks the device and a secret-sharing scheme allows us to reconstruct this master key in the presence of k-out-of-n items. We extend this basic scheme in various directions, e.g. by allowing items to issue a dynamically variable number of shares based on how confident they are that the user is present. The position we argue in this paper is that a multi-dimensional approach to authentication that fuses several contextual inputs, similar to that already adopted by major web sites, can also bring advantages at the local scale.
External DOI: https://doi.org/10.1145/2638728.2641705
This record's URL: https://www.repository.cam.ac.uk/handle/1810/245640