Apparently this is old news in the security world, but in a world where critical passwords are still on post-it notes on the monitor, it’s still interesting. Hackers can read your keystrokes through the power grid, Currently it’s only been proven to a distance of about 15 meters which means they have to get access to an outlet in the same building, even if it can be floors away. And the researchers claim this is done with only $500 in equipment, so it stands to reason that specialized equipment could do better.

The Slashdot discussion points out that defenses against this technology were declassified over 20 years ago. (See TEMPEST.)

Most importantly, there’s a fun way to try this at home if you have a CRT monitor and a short wave radio (unfortunately I have neither), Tempest for Eliza is a program that will do essentially the reverse of this hack — vary what’s being shown on your monitor to do something specific with the leaking electromagnetic waves: playing a song in a short wave radio frequency.