Computer chip noise may betray code

May 12, 2004 | Source: NewScientist.com News

The noise emitted by computer chips could help code breakers decipher encrypted messages.

The high-frequency audio produced by CPUs allows for distinguishing between different cryptographic keys being processed by the chip, based on the frequency of the sound emitted, and the length of a string of characters by measuring the duration of certain sounds.

Other code-breaking techniques include power-supply fluctuations exhibited by chips, electromagnetic emanations from a monitor, and indirect light from a computer monitor.