By Elinor Mills
March 19, 2008
VANCOUVER, B.C. -- Presenters at the CanSecWest security conference
detailed on Thursday how they can sniff data by analyzing keystroke
vibrations using a laser trained on a shiny laptop or through electrical
signals coming from a PC connected to a PS/2 keyboard and plugged into a
Using equipment costing about $80, researchers from Inverse Path were
able to point a laser on the reflective surface of a laptop between 50
feet and 100 feet away and determine what letters were typed.
Chief Security Engineer Andrea Barisani and hardware hacker Daniele
Bianco used a handmade laser microphone device and a photo diode to
measure the vibrations, software for analyzing the spectrograms of
frequencies from different keystrokes, as well as technology to apply
the data to a dictionary to try to guess the words. They used a
technique called dynamic time warping that's typically used for speech
recognition applications, to measure the similarity of signals.
Line-of-sight on the laptop is needed, but it works through a glass
window, they said. Using an infrared laser would prevent a victim from
knowing they were being spied on.
The only real way to mitigate against this type of spying would be to
change your typing position and mistype words, Barisani said.
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