Optical Tempest FAQ

[Dave Emery]

On Thu, Dec 02, 2004 at 12:32:09PM -0500, Tyler Durden wrote:
> However, his discussion would indicate that the various practical concerns 
> and limitations probably limit this to very niche-type applications...I'd 
> bet that it's very rare when such a trechnique is both needed as well as 
> useful, given the time, the subject and the place.
> 
> -TD

	The big problem with this technology (and classic Van Eck
electromagnetic interception too)  is that more and more folks are using
LCD screens or other display devices that do not do single thread raster
scans of what they are displaying.   Thus no single signal exists  to
detect with all the pixels of the image in it.

	In fact the greater hazard may sometimes be from red, yellow or
green LEDs on the front of equipment that are directly driven with
real data in order to allow troubleshooting - recovering data from one
of those at a distance using a good telescope may be possible and most
people don't think of the gentle flicker of the LED as carrying actual
information that could be intercepted.

-- 
   Dave Emery N1PRE,  die at dieconsulting.com  DIE Consulting, Weston, Mass 02493