From: Dale Thorn <dthorn@gte.net>
Date: Tue, 11 Mar 1997 23:33:37 -0800 (PST)
To: TruthMonger <an7575@anon.nymserver.com>
Subject: Re: TEMPEST protection
In-Reply-To: <199703120604.AAA00512@manifold.algebra.com>
Message-ID: <33265C33.15BB@gte.net>
MIME-Version: 1.0
Content-Type: text/plain


TruthMonger wrote:
>   Having had electro-shock therapy, I consider myself
> somewhat of an expert in this area.
>   I have an outdated computer which I set next to my new
> computer, and I have self-running programs running on it
> all the time. I also add a keyboard input device when I
> want a little extra *noise* in the air. (It uses those
> *ducks* that swing up and down, dipping their beaks in
> a glass of water.)

Actually, the computer you type on will be very easy to pick out
of the noise field with modest spy equipment sitting down the street.

There's a company (I lost the brochure) who sell EM attenuator
material, some preconfigured, and presumably some bulk.  It should
be easy to find on the Web.  Once you get some really dramatic
attenuation, particularly of the keyboard (and particularly during
password confirmations, etc.), you should do your own preliminary
monitoring with some of those band-sweep gadgets.  Steady noise
of course is nothing compared to the spikes from some of the keyboard
outputs...

Once you've identified all (we can hope, can't we) of the problem
signals still leaking through the shielding (albeit at greatly
reduced levels), you can direct different kinds of efforts there,
including random noise from other computers which use the exact
same output devices.

HP has been selling Tempest-approved PC's since the early 1980's
(if not before), and at not too steep a price, either, so it can't
be all that difficult, once you get a handle on it.