Italian version
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29.06.04 Keyboard Acoustic Emanations, spying the sound of a keyboard.
After becoming popular thanks to the novels and movies centered on them, espionage techniques have recently become a science in themselves, losing the sci-fi aura which surrounded them and turning into a new threat to privacy. In May 2002, a way to spy the image on a monitor using only the light emitted was announced, while very recently a paper written by two researchers at IBM, Dmitri Asonov and Rakesh Agrawal, and presented at the IEEE Symposium on Security and Privacy, entitled 'Keyboard Acoustic Emanations', explains how to sniff the keys pressed on a keyboard using only their sound. The researchers, in fact, have found that in computer keyboards, as well as in telephone and ATM keyboards, each key emits a different and peculiar sound when it's pressed and released, due to the rubber membrane under it. Using a common microphone (or even transmitting the sound with a cell phone) and a software based on neural network algorithms, the accuracy level is over 80%, and a calibration period aimed at a particular keyboard model allows to use the same settings on every keyboard of that model. The authors say that closing the door or covering the keyboard with a rubber protection it's enough to render this technique useless.