Computer scientists have devised an attack that reliably extracts secret cryptographic keys by capturing the high-pitched sounds coming from a computer while it displays an encrypted message.The technique, outlined in a research paper published Wednesday, has already been shown to successfully recover a 4096-bit RSA key used to decrypt e-mails by GNU Privacy Guard, a popular open source implementation of the OpenPGP standard. Publication of the new attack was coordinated with the release of a GnuPG update rated as "important" that contains countermeasures for preventing the attack. But the scientists warned that a variety of other applications are also susceptible to the same acoustic cryptanalysis attack. In many cases, the sound leaking the keys can be captured by a standard smartphone positioned close to a targeted computer as it decrypts an e-mail known to the attackers.
That's right. With the right software, a guy can glean the encryption keys off your computer with a smartphone. By -listening- to it.
Tinfoil hat ain't tight enough, is it?