Fine-Grained Secure Localization for 802.11 Networks

The erosion of well-defined network boundaries makes the use of identity a necessary but insufficient means of authentication in numerous contexts. In a number of settings, proving a user's location may in fact be more critical. In this work, we use standard 802.11 access points to broadcast cryptographic tokens at a variety of power levels. Clients attempting to prove their location report the overheard tokens to a controller. To improve certainty, the controller then requests that desktop machines with inexpensive wireless radios in the macro-vicinity broadcast an additional round of tokens. In so doing, we are able to develop a fine-grained, non-forgeable wireless localization system that is resistant to sophisticated attackers attempting to spoof their physical location.