From: Roger Williams <roger@coelacanth.com>
Date: Thu, 14 Mar 1996 15:50:59 +0800
To: cypherpunks@toad.com
Subject: Re: Beat Remote Monitor Snooping?
In-Reply-To: <Pine.SV4.3.91.960313223844.19338E-100000@larry.infi.net>
Message-ID: <9603140628.AA4032@sturgeon.coelacanth.com>
MIME-Version: 1.0
Content-Type: text/plain


>>>>> 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/