Eavesdropping on Phone Conversations Through Vibrations

The text discusses emissions security risks and side-channel eavesdropping, explaining how mechanical vibrations and bidirectional transducers enable surveillance via laser microphones on windows and potentially RF or radar-like approaches. It outlines how wavelength and frequency relationships constrain practicality, the impact on signal-to-noise, and the possibility of using ISM-band devices, underscoring that energy gapping is more accurate than air gapping for mitigating such threats.