How Vulnerable Are Computers to an 80-Year-Old Spy Technique? Congress Wants Answers

A pair of US lawmakers are calling for an investigation into how easily spies can steal information based on devices’ electromagnetic and acoustic leaks—a spying trick the NSA once codenamed TEMPEST.

Computers leak secrets. Not just through invasive ad tracking, data-stealing malware, and your ill-advised oversharing on social media, but through physics. The movements of a hard drive's components, keystrokes on a keyboard, even the electric charge in a semiconductor's wires produce radio waves, sound, and vibrations that transmit in all directions and can—when picked up by someone with sufficiently sensitive equipment and enough spycraft to decipher those signals—reveal your private data and activities.