Keystoke Logging By Sound Alone?
Researchers at the University of California, Berkeley have discovered a way of snooping on typists by analysing the sounds of the keyboard being used. The technique is allegedly 96% accurate (more than enough to get the gist of a document or email) and requires only 10 minutes of calibration.
The technique is simple and familiar to cryptographers everywhere. The sound of a typist hitting the ‘e’ key is different to the ’s’ key and so on. By analysing the different sounds, snoopers can woks out the relative frequency of use for each key. From that point on it’s simply a case of knowing what language the typist would be using and applying a statistical formula along the lines of ‘most common sound must be the e as that is the most common letter’. Think of it as a normal substitution cypher.
Of course, there’s a little more to it than that and the researchers also applied spelling and grammar rules to the text to refine it, however, the technique is apparently easy enough to duplicate with a home set up and for that reason the source code of the software is being kept under wraps.
The researchers are also convinced they that aren’t breaking new ground here. “If you believe the [National Security Agency] hasn’t done this already, you’re naive,” they are quoted as saying in PC World.
Add comment September 15th, 2005
Showing Sony how European gamers should be treated, Microsoft has announced an almost simultaneous worldwide launch of the Xbox 360.