At 07:12 PM 11/13/00 -0600, Neil Johnson wrote:
The general idea is to pick up and decode the RF emissions generated by the CPU, Memory, I/O and Video systems to figure out what the computer is doing.
It takes some work (not as much as you would think), but there have been documented demonstrations where the video signals from a PC were picked up and reproduced on another monitor several hundred feet away.
TEMPEST is the "code" name for the U.S. Governments standards for shielding computer equipment used for classified work inorder to prevent such eavesdropping.
The technique is often referred to as "Van Eck Phreaking" (sic).
As I recall one suggested method in the paper involved some cleaver manipulation of pixel intensities and/or location to create the equivalent of a high process gain spread spectrum signal. Brilliant concept. steve