Microphones placed near keyboards can record keystrokes.

[David Farber <dave () farber net>]

Begin forwarded message:

From: Joseph Lorenzo Hall <joehall () gmail com>
Date: September 13, 2005 4:25:43 PM EDT
To: Dave Farber <dave () farber net>
Subject: Microphones placed near keyboards can record keystrokes.
Reply-To: joehall () pobox com


Here's a second try at submitting this one to IP... : )

Since I last sent this, this research has made [Ed Felten's blog][6],
[Bruce Schneier's blog][7] and [Slashdot][8].  I can imagine some
IPers would have interesting things to say.  My own thoughts are
[here][9]. best, Joe

----

<http://tygar-blog.com/2005/09/keyboard-acoustic-emanations- 
revisited.html>

## September 2, 2005

### Keyboard Acoustic Emanations Revisited

Microphones placed near keyboards can record keystrokes. [Li
Zhuang][1], [Feng Zhou][2], and [I (Doug Tygar)][3] 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.

Our paper on this work will appear in November 2005 at the ACM
Conference on Computer and Communications Security.

A preprint of our paper describing this work is available at
[keyboard-emanations.org][4]. Copies of other papers by me are
available at [my publications web site][5].

Doug Tygar 9/02/2005 08:33:00 AM

[1]: http://www.cs.berkeley.edu/~zl/
[2]: http://www.cs.berkeley.edu/~zf/
[3]: http://www.cs.berkeley.edu/~tygar/
[4]: http://keyboard-emanations.org/
[5]: http://www.cs.berkeley.edu/~tygar/publications.htm
[6]: http://www.freedom-to-tinker.com/?p=893
[7]: http://www.schneier.com/blog/archives/2005/09/snooping_on_tex.html
[8]: http://it.slashdot.org/article.pl? 
sid=05/09/13/1644259&tid=172&tid=218
[9]: http://josephhall.org/nqb2/index.php/2005/09/04/mic_strokes

--
Joseph Lorenzo Hall
UC Berkeley, SIMS PhD Student
<http://josephhall.org/>

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