The Measurable Environment as Nonintrusive Authentication Factor on the Example of WiFi Beacon Frames

We explore a method to fingerprint a location in terms of its measurable environment to create an authentication factor that is nonintrusive in the sense that a user is not required to engage in the authentication process actively. Exemplary, we describe the measurable environment by beacon frames from the WiFi access points in the user’s proximity. To use the measurable environment for authentication, measurements must be sufficiently discriminating between locations and similar at the same location. An authentication factor built from the measurable environment allows us to describe a user’s location in terms of measurable signals. Describing a location in terms of its measurable signals implies that we do not require an actual geographical mapping of the user’s location; comparing the measured signals is sufficient to create a location-based authentication factor. Only recognizing an earlier observed environment distinguishes our approach from other location-based authentication factors. We elaborate on using signals in the user’s environment in the background without user involvement to create a privacy-preserving but nonintrusive authentication factor suitable for integration into existing multi-factor authentication schemes.