Location Proof via Passive RFID Tags

With the surge in location-aware applications and prevalence of RFID tags comes a demand for providing location proof service with minimal cost. We introduce two protocols that provide secure and accurate location proof service using passive RFID tags. Both protocols are lightweight, adaptive and cost-effective. The first protocol assumes the connection of a user to the remote server. The second protocol does not require real time interactions with the server. Instead, it uses the self-reported time of local RFID reader (such as a cell phone), which may be biased. The user can upload the information to the server later to obtain the location proof. The paper presents a solution to derive users' actual time of presence in the absence of a reliable clock, assuming an arbitrarily large number of falsified data points from malicious users.