Computers make noises, the researchers explain, far beyond the whirring of the fan. The CPU, for example, emits a high pitched noise as it operates, fluctuating depending on which operations it is performing—other components do likewise. Suspecting that they might be able to exploit this characteristic of computers, the researchers set about creating software to interpret noise data obtained using simple microphones and very little other equipment. They also focused exclusively on trying to achieve one single feat: deciphering an RSA encryption key. After much trial and effort, the researchers found it could be done without much effort.
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