Beat Remote Monitor Snooping?
I know that monitors emit RF signals that can be detected and decoded for a considerable distance. I have a question about this. Obviously, the difference between black and white (white text on black background, or vice versa) would be the most detectable, because the difference in signal levels would be the greatest. Would it be possible to reduce or prevent this kind of snooping by using color schemes that all use the same signal levels? For example, the color purple uses the red and blue color guns, and yellow uses the red and green color guns. Would purple text on a yellow background be able to be read by a remote snooper? If not, then perhaps these color schemes could be used to echo pass phrases--assuming the user isn't worried about someone looking over their shoulder. Any comments? Jonathan Wienke
Visual contrast is not the same thing as frequency diffrence. It is quite easy to measure extremely small changes of phase. As in, your plain-vanilla FM receiver. What's his name put this stuff together in the mid 1930's. Nice try, but no cigar.
Alan Horowitz <alanh@infi.net> writes:
Visual contrast is not the same thing as frequency diffrence. It is quite easy to measure extremely small changes of phase.
Apropos of *what*?! If it was an NTSC colour TV; yes, you could measure the colour by the phase of the 3.579 colour burst. But modern computer monitors (i.e. VGA) don't represent colour that way at all -- they use separate red, green, and blue video signals. And the original poster is correct -- it is extremely difficult to determine which guns are generating any given pixel, using van Eck monitoring. The only com/mil ELINT demo I've ever seen of a VGA monitor generated a greyscale display.
Nice try, but no cigar.
If the shoe fits... -- Roger Williams PGP key available from PGP public keyservers Coelacanth Engineering consulting & turnkey product development Middleborough, MA wireless * DSP-based instrumentation * ATE tel +1 508 947-8049 * fax +1 508 947-9118 * http://www.coelacanth.com/
Can you please take me off your mailing list. Thankyou. firebrd123@mail.interconnect.net
Firebrd123 writes:
Can you please take me off your mailing list. Thankyou. firebrd123@mail.interconnect.net
No, we can't take you off the list. We are the *recipients* of the mailing list, not the people who run it. We have no access to the machine that contains the list management software. You get off by mailing to the same address you mailed to to get on. I leave that information as an exercise to the reader.
participants (5)
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Alan Horowitz -
firebrd123＠ns.interconnect.net -
JonWienke＠aol.com -
Perry E. Metzger -
Roger Williams