Proof of a user's identity is not always a sufficient means for making an authorization decision. In an increasing set of circumstances, knowledge of physical location provides additional and necessary context for making decisions about resource access. For example, sensitive information stored on a laptop (e.g. customer records, social security numbers, etc), may require additional protections if a user operates outside of an approved area. However, current localization techniques based on signal strength reporting or specialized hardware fail to achieve this goal. In this paper, we design, develop, deploy and measure a system which securely determines the location of a user to within one meter through using only off-the-shelf 802.11 and Bluetooth equipment. We apply this equipment in a two-phased challengeresponse protocol: first determining the general area of the client in the Regionalization phase and then pinpointing it in the Localization phase. Using nearly 32,000 data poi...
Patrick Traynor, Joshua Schiffman, Thomas F. La Po