RMDM: Using Random Meta-Atoms to Send Directional Misinformation to Eavesdroppers

In this paper, we propose RMDM, Random Meta-atoms enabled Directional Misinformation, a novel system that enables a wireless transmitter to program a transmissive metasurface to send misinformation towards eavesdroppers while ensuring the correct information is received at the legitimate receiver. To do so, we design a metasurface with angular-dependent channel responses that alter the phase and amplitude of the transmitted symbol in different ways along different angular directions. We show how randomly selected groups of meta-atoms can be reconfigured so that the symbol constellation in the eavesdropper's direction is randomly transformed for each symbol. Moreover, our design includes a baseband correction, prior to transmission, to eliminate the metasurface's impact in the intended user's direction. Our experimental results show that the eavesdropper's error probability increases to almost 0.5 after an angular separation of only 4° away from the legitimate user's direction, forcing the eavesdropper to be very close to correctly intercept the information.