Security researchers found that poor shielding on some keyboard cables means useful data can be leaked about each character typed. By analysing the information leaking onto power circuits, the researchers could see what a target was typing.The attack has been demonstrated to work at a distance of up to 15m, but refinement may mean it could work over much longer distances.

From a BBC Article ... http://news.bbc.co.uk/2/hi/technology/8147534.stm

Security researchers found that poor shielding on some keyboard cables means useful data can be leaked about each character typed. By analysing the information leaking onto power circuits, the researchers could see what a target was typing.The attack has been demonstrated to work at a distance of up to 15m, but refinement may mean it could work over much longer distances.

From a BBC Article ... http://news.bbc.co.uk/2/hi/technology/8147534.stm

Back in the 1970's we used to have black power filters on all our airforce ground based coms devices to stop people from doing exactly what you say here.

Oh ya all our commfac had secure rooms with filtering on every wire in and out. One side is always called red and the other the black zone. Rooms are also screened and grounded. Its not as bad as it was because everything works a lower levels then before. Then the range was in the 100's of meters. Contact bounces of various equipment even more, a dead giveaway to location the of an enemy or yours.

One of my books has a chapter about intercepting what people are typing based on analysis of the sound and timing of their keystrokes. It's amazing what you can do if you have endless amounts of time to waste!

Edited July 14, 200916 yr by Crushdepth