Secure location verification using radio broadcast

Secure location verification is a recently stated problem that has a number of practical applications. The problem requires a wireless sensor network to confirm that a potentially malicious prover is located in a designated area. The original solution to the problem, as well as solutions to related problems, exploits the difference between propagation speeds of radio and sound waves to estimate the position of the prover. In this paper, we propose a solution that leverages the broadcast nature of the radio signal emitted by the prover and the distributed topology of the network. The idea is to separate the functions of the sensors. Some sensors are placed such that they receive the signal from the prover if it is inside the protected area. The others are positioned so that they can only receive the signal from the prover outside the area. Hence, the latter sensors reject the prover if they hear its signal. Our solution is versatile and it deals with provers using either omni-directional or directional propagation of radio signals without requiring any special hardware besides a radio transceiver. We estimate the bounds on the number of sensors required to protect the areas of various shapes and extend our solution to handle complex radio signal propagation, optimize sensor placement, and operate without precise topology information.