Saturday, March 21, 2009

Sniffing keystrokes via laser and keyboard power

cnet
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 socket.

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.

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