] The following demonstrates some preliminary results in
] the analysis of acoustic emanations from personal
] computers, showing them to be a surprisingly rich source
] of information on CPU activity.

A powerful method for extracting information from supposedly secure systems is side-channel attacks: cryptanalytic techniques that rely on information unintentionally leaked by computing devices. Most side-channel attack research has focused on electromagnetic emanations (TEMPEST), power consumption and, recently, diffuse visible light from CRT displays. The oldest eavesdropping channel, namely acoustic emanations, has received little attention. Our preliminary analysis of acoustic emanations from personal computers shows them to be a surprisingly rich source of information on CPU activity.

A powerful method for extracting information from supposedly secure systems is side-channel attacks: cryptanalytic techniques that rely on information unintentionally leaked by computing devices. Most side-channel attack research has focused on electromagnetic emanations (TEMPEST), power consumption and, recently, diffuse visible light from CRT displays. The oldest eavesdropping channel, namely acoustic emanations, has received little attention. Our preliminary analysis of acoustic emanations from personal computers shows them to be a surprisingly rich source of information on CPU activity.

Not only is this interesting, but it also gives me a good reason for using my IBM Thinkpad as a mobile development platform. According to this, they do not give away much information that can be gathered using these techniques.

Our preliminary analysis of acoustic emanations from personal computers shows them to be a surprisingly rich source of information on CPU activity.

This fact should be obvious to anyone who's ever tried to make low SNR recordings with a $5 sound card.