mmEcho: A mmWave-based Acoustic Eavesdropping Method

Pengfei Hu, Wenhao Li, Riccardo Spolaor, Xiuzhen Cheng

Abstract: Acoustic eavesdropping on private or confidential spaces poses a significant privacy threat. While soundproof rooms can mitigate these risks to some extent, they are unable to counter sophisticated eavesdropping, which has gained attention in recent research. This paper presents mmEcho, an acoustic eavesdropping system that employs millimeter-wave radio signals to accurately measure micrometer-level vibrations induced by sound waves. Compared to prior approaches, our method achieves high accuracy in eavesdropping without requiring prior knowledge about the victim. We evaluate the performance of mmEcho under extensive real-world settings and scenarios. Our results show that mmEcho can accurately reconstruct audio from sources.