It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Originally posted by Djarums
Does the keyboard make a different sound when I hit "p" than when I hit "q"??
Of course I understand the amount of keystrokes could be easily heard, but which keys? Based on sound?
Microphones placed near keyboards can record keystrokes. Li Zhuang, Feng Zhou, and I have developed a set of algorithms for recreating the material typed directly from the keystrokes. Unlike previous approaches, our algorithms require no information about the typist, keyboard, room, or text typed. Unlike previous approaches, our algorithms do not require any “labeled training data” (matching acoustic recordings to the actual text typed by a particular typist.) In contrast, our algorithm can use data from a cheap microphone in the room with a typist, collect ten minutes worth of data, and the algorithm will be able to recover the typed text. In fact, once our algorithm has ten minutes worth of typed English text, it can recover arbitrary text, such as passwords. Even if the typist uses a “quiet keyboard”, we can still recover the text. And our work further suggests that the microphone need not be placed in a room — a parabolic microphone outside the room would work equally well at recovering the signals.
Researchers Recover Typed Text Using Audio Recording of Keystrokes By Sarah Yang, Media Relations 14 September 2005
The researchers were able to take several 10-minute sound recordings of users typing at a keyboard, feed the audio into a computer, and use an algorithm to recover up to 96 percent of the characters entered.
"It's a form of acoustical spying that should raise red flags among computer security and privacy experts," said Doug Tygar, UC Berkeley professor of computer science and information management and principal investigator of the study.
What makes the technique feasible is that each keystroke makes a relatively distinct sound, however subtle, when hit. Typical users type about 300 characters per minute, leaving enough time for a computer to isolate the sounds of individual keystrokes and categorize the letters based upon the statistical characteristics of English text.
"Using statistical learning theory, the computer can categorize the sounds of each key as it's struck and develop a good first guess with an accuracy of 60 percent for characters, and 20 percent for words," said Li Zhuang, a UC Berkeley Ph.D. student in computer science and lead author of the study. "We then use spelling and grammar checks to refine the results, which increased the character accuracy to 70 percent and the word accuracy to 50 percent. The text is somewhat readable at this point."
But that's not the end. The recording is then played back repeatedly in a feedback loop to "train" the computer to increase its accuracy until no significant improvement is seen. In the UC Berkeley experiments, three feedback cycles were often enough to obtain recovery rates of 88 percent for words and 96 percent for characters.
Once the system is trained, recovering the text became more straightforward, even if the text was a password and not an English word. After just 20 attempts, the researchers were able to retrieve 90 percent of five-character passwords, 77 percent of eight-character passwords and 69 percent of 10-character passwords.
Originally posted by they see ALL
that is so cool...
before this, keyloggers where the best tools to use to see what a person was typing...