We consider the problem of secure localization in WLANs. Here the problem of locating a client is compounded by its malicious attempts to deceive the localization system. We propose a robust scheme, SecLoc, to address this problem. SecLoc leverages the feature of WLAN transmitters whereby they can perform transmissions using multiple distinct power levels. SecLoc uses an infrastructure of reference points in the area where a client's location has to be determined. Transmitters are expected to send messages at different power levels such that every location in the system corresponds to a unique set of messages. The client and the reference points subsequently report received messages to SecLoc's localization infrastructure. SecLoc then determines the location of the client by comparing the messages reported by the client with the messages reported by the reference points. The scheme is flexible in that it trades off security for cost of deployment. In addition, the scheme is self configurable since it does not require any manual efforts for building a map of messages to locations at which they are received. We perform extensive experiments in order to study the performance of the proposed scheme. Performance is evaluated both in terms of location accuracy and resilience to malicious client behavior. We observe that SecLoc is able to determine the location of clients within 3-8 feet of their true location. Further, SecLoc can detect malicious behavior with 80-100% accuracy with a false positive rate between 1-2%.
['Abhrajit Ghosh', 'Vikram Kaul', 'David Famolari']
An Approach to Secure Localization in WLANs