[quote]Many computers emit a high-pitched noise during operation, due to vibration in some of their electronic components. These acoustic emanations are more than a nuisance: they can convey information about the software running on the computer and, in particular, leak sensitive information about security-related computations. In a preliminary presentation, we have shown that different RSA keys induce different sound patterns, but it was not clear how to extract individual key bits. The main problem was the very low bandwidth of the acoustic side channel (under 20 kHz using common microphones, and a few hundred kHz using ultrasound microphones), many orders of magnitude below the GHz-scale clock rates of the attacked computers. Here, we describe a new acoustic cryptanalysis key extraction attack, applicable to GnuPG's current implementation of RSA. The attack can extract full 4096-bit RSA decryption keys from laptop computers (of various models), within an hour, using the sound generated by the computer during the decryption of some chosen ciphertexts. We experimentally demonstrate that such attacks can be carried out, using either a plain mobile phone placed next to the computer, or a more sensitive microphone placed 4 meters away. Beyond acoustics, we demonstrate that a similar low-bandwidth attack can be performed by measuring the electric potential of a computer chassis. A suitably-equipped attacker need merely touch the target computer with his bare hand, or get the required leakage information from the ground wires at the remote end of VGA, USB or Ethernet cables.[/quote] [quote]Q5: What are some examples of attack scenarios? We discuss some prospective attacks in our paper. In a nutshell: - Install an attack app on your phone. Set up a meeting with the victim and place the phone on the desk next to his laptop (see Q2). - Break into the victim's phone, install the attack app, and wait until the victim inadvertently places his phone next to the target laptop. - Construct a web page use the microphone of the computer running the browser (using Flash or HTML Media Capture, under some excuse such as VoIP chat). When the user permits the microphone access, use it to steal the user's secret key. - Put your stash of eavesdropping bugs and laser microphones to a new use. - Send your server to a colocation facility, with a good microphone inside the box, and then acoustically extract keys from all nearby servers. - Get near a TEMPEST/1-92 protected machine, such as the one pictured to the right, place a microphone next to its ventilation holes, and extract its supposedly-protected secrets.[/quote]OMG. tl;dr Encryption keys can be stolen from a device sitting up to 4 metres away by analysing the sound the computer makes. http://www.cs.tau.ac.il/~tromer/acoustic/