Recording keyboard clicks
New method of computer espionage: recording keyboard clicks
Researchers at Berkley University showed that an audio recording of keyboard clicks makes it possible to recover the typed text with high accuracy. A group of scientists managed to make out 96% of information using a ten-minute record.
This type of espionage is acoustic, which does not allow information security experts prevent data leaks. A spy will only have to place a microphone near the keyboard and he will get full access to the information he is interested in. The only drawback is that the spy's physical interference is required.
The complete official information will be presented to the community on November 10 at the Name conference on computer security.
The information recovery method is based on the distinctions of keyboard clicks that are indistinguishable for a human hear, but quite enough to be processed by computers. Besides, the relatively low speed of typing (users type not more than 300 characters per minute) does not allow discrete sounds to merge into a monotonous sound, which make it possible to distinguish between them.
After that the statistical method of recognizing the exact phrase comes in. Analysis is used to determine the probability of typing one or another word depending on how frequently it is used in communication.
After this stage is over, the computer recognizes 60% of characters. A grammar check and stylistic analysis will add another 10 percent.
Finally, it is possible to increase the accuracy of recognition above 90% by training the program.