From: nobody@shell.portal.com
Date: Mon, 8 Nov 93 22:33:11 PST
To: cypherpunks@toad.com
Subject: TEMPEST Defenses and average Van Eck Gear...
Message-ID: <9311090632.AA27475@jobe.shell.portal.com>
MIME-Version: 1.0
Content-Type: text/plain


Hi All....

    #1 using personal countermeasures against emanation
eavesdropping IS defnitely NOT illegal.
    #2 So few people have actual experience with Van Eck gear either
the ConsumerTronics Model or the Pk Electronics German Device or
the version made by a firm in england. 
First of all Van Eck Monitor Eavesdropping seems to be a deeply shrouded
subject even for most engineers and for most c-punks.

Its basically a system for reconstruction of the sync signal for
monitor radiation received with a standard tuning mechanism...
It is VERY similar to various Pay TV Decode Schemes mentioned and
detailed in Radio Electronics over the past several years combined with a 
Monitor and a high gain amplified antenna... VERY specific
plans are available from consumertronics for 25.00.

And protecting against Van Eck can be extensive as a faraday cage or
a subtle as conductive Wallpaper. floors, doors and windows...
it really depends on the economic resources of your adversary and
how much of a bother you are...

      Sam Hill
p.s. Careful monitor placement if you have A LOT(at least 50) computers/
monitors can use noise data displayed on non-critical monitors to
mask emanations of a single monitor where critical data IS handled..
$3-25k spent by a firm on acquiring the technology for internal
survey can save LOTS of money from having to Faraday Cage an Entire Data
Center...

As for eavesdropping on bus/circuit emanation we will take that up
at another time