Another growth industry upcoming ...

Contractors that radio proof a panic room by laying out wall to wall, floor to ceiling, grounded wire mesh painted over with the shielding paint we use inside guitar cavities.

Of course your cellphone won't work but them's the breaks.

This is some seriously weird stuff. :o

http://www.pcworld.com/article/2082200/listen-up-rsa-keys-snatched-by-recording-cpu-sounds-with-a-phone.html

"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," the paper's authors wrote. "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."

I can't help but remember the other post about malware communicating through such techniques:

http://www.foolsdesign.org/viewtopic.php?f=4&t=222

Apparently to ensure messages are sent secretly you not only need a very good encryption algorithm, but also a sound-proof Faraday cage.