Link to the paper: http://www.cs.berkeley.edu/~tygar/papers/Keyboard_Acoustic_Emanations_Revisited/tiss.preprint.pdf http://www.cs.berkeley.edu/~tygar/papers/Ke

Link to the paper: http://www.cs.berkeley.edu/~tygar/papers/Keyboard_Acoustic_Emanations_Revisited/tiss.preprint.pdf http://www.cs.berkeley.edu/~tygar/papers/Keyboard_Acoustic_E... It's pretty interesting. It's an algorithm which, given a recording of you typing out several HN comments, can generate an acoustic profile of how you type on your particular keyboard. By assuming that you're typing English, it can infer what words you're typing based on its rough guess, and then it can train itself to recognize keystroke sounds that it previously got wrong. After a few times of doing this, it claims to be accurate enough to recover your passwords from a recording of you typing them in.