NSA Releases Historical Documents on TEMPEST 121
sgunhouse writes to mention Wired's Threat Level has a piece on a recently-declassified document detailing the history of TEMPEST. "It was 1943, and an engineer with Bell Telephone was working on one of the U.S. government's most sensitive and important pieces of wartime machinery, a Bell Telephone model 131-B2. It was a top secret encrypted teletype terminal used by the Army and Navy to transmit wartime communications that could defy German and Japanese cryptanalysis. Then he noticed something odd. Far across the lab, a freestanding oscilloscope had developed a habit of spiking every time the teletype encrypted a letter. Upon closer inspection, the spikes could actually be translated into the plain message the machine was processing. Though he likely didn't know it at the time, the engineer had just discovered that all information processing machines send their secrets into the electromagnetic ether."
Re:Maybe the silliest consequence? (Score:3, Insightful)
The NSA is the number one employer of mathematicians in the USA. The Russians are also supposed to be very good. If there is a way to extract intelligence from the noise, they probably know about it. If it's electrical, it radiates. If it radiates, someone else can detect it. If the signal is weak, they can build a better antenna, design a more sensitive receiver, and use more sophisticated signal processing.
Look at your average PC. The keyboard and display are broadcasting tons of information to anyone who has the right equipment.