New Scientist: Computer chip noise may betray code

5/11/04
"The noise emitted by computer chips could help code breakers decipher encrypted messages, according to preliminary research carried out at the Weizmann Institute in Israel.
Adi Shamir and Eran Tromer sampled the high-frequency audio produced by computer central processing units (CPU) ... They discovered that they could distinguish between different cryptographic keys being processed by the chip, according to the frequency of the sound emitted. They also found they could determine the length of a string of characters by measuring the duration of certain sounds."
Very interesting. As fancy as computers are, it all still comes down to the physics of heat, sound, etc.