In-Band Sensing of the Adversary’s Channel for Secure Communication in Wireless Channels

We propose a model of secure communication over wireless channels in which the legitimate parties leverage Radio Tomographic Imaging (RTI) to learn the adversary. Specifically, we model the results of RTI as an "in band" sensing channel that provides causal information about the eavesdropper's path-loss to the transmitter. This ability to learn the path-loss is exploited to achieve secrecy, even in presence of an eavesdropper that moves to optimize its path-loss and improves its eavesdropping. We show that the secrecy rates achieved are the same as those that would have been obtained with hindsight, had the transmitter known the average path-loss ahead of time.