Acoustic cryptanalysis: On nosy people and noisy machines
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…
This is from the same author. It looks like RSA-1024 is safe for now, but not for too much longer!
…Using this hypothetical device (and ignoring the initial R&D costs), it appears possible to break a 1024-bit RSA key in one year using a device whose cost is about $10M (previous predictions were in the trillions of dollars)…