Wu Jinzhou<\/p>\n
VGA cable and display unit are typical mediums for information transmission and output in
\na computer system. Since VGA cable is made by metal wires and carries display signal, it
\neventually emits electromagnetic waves. These emanations reveal display image and may
\ncause private and sensitive information leakage. This report describes the experiments and
\nanalysis of the interception of personal computer\u2019s display image using emanation of
\nelectromagnetic wave form VGA cable. In the experiment, a modern full HD flat LCD
\nscreen connected to a personal computer via VGA cable is used as the target display, the
\ninterception is performed under normal office\/home environment condition. In our work, we
\nhave (1) studied the computer display monitor timing and identified the sync information,
\n(2) intercept the electromagnetic emanations from VGA cable, (3) processed the intercepted
\ndata and restored the display image on the target screen and (4) analyzed the image
\nreconstruction results by repeating step (2) at various distance. We have fully or partially
\nrestored the display image at the distance form less than 1 cm up to 30 cm away form the
\nsignal source. Both observation results and analysis results suggest that the bright text on
\nthe dark background is more secure than the dark text on the bright background in against of
\ninterception under experimental settings.<\/p>\n