From: Jim Choate <ravage@ssz.com>
Date: Mon, 9 Feb 1998 22:28:24 +0800
To: cypherpunks@ssz.com (Cypherpunks Distributed Remailer)
Subject: Re: Laptop TEMPEST (fwd)
Message-ID: <199802091430.IAA20623@einstein.ssz.com>
MIME-Version: 1.0
Content-Type: text



Forwarded message:

> Subject: Re: Laptop TEMPEST
> From: Ryan Lackey <rdl@mit.edu>
> Date: 09 Feb 1998 02:34:15 -0500

> FCC RF/EMC testing is well nigh useless for TEMPEST protection.

I disagree, it would give you a gross baseline on the total emissions
between monitors and laptops. That field strenght measurement would at least
allow you to calculate radiuses of equal strength to calculate approximately
how far the emissions are from each class of device for equal probabilities
of detection. One of the specific goals is to measure how effective the
device is at effecting other co-located devices (such as seeing ghost images
on other monitors or causing static in paging equipment).

I suspect one could do it with a spectrum analyzer or a grid dip meter.

> I imagine there may be some other "dual use" technologies through for
> testing TEMPEST equipment.  Perhaps some medical equipment has stringent
> stray emanation specs?

We're not trying to bring the individual vertical retraces out of the
chaff...we're trying to calculate the total comparitive emission strengths.
If that isn't high enough then trying to get individual componants of that
field will be useless.


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