From: Markus Kuhn <Markus.Kuhn@cl.cam.ac.uk>
Date: Tue, 10 Feb 1998 01:46:07 +0800
To: cypherpunks@toad.com
Subject: Re: Soft Tempest
In-Reply-To: <199802090715.CAA24788@the-great-machine.mit.edu>
Message-ID: <E0y1x0U-0000eF-00@heaton.cl.cam.ac.uk>
MIME-Version: 1.0
Content-Type: text/plain



Ryan Lackey wrote on 1998-02-09 07:15 UTC:
> The paper pretty clearly says laptop LCDs are not sufficiently quiet.  Until
> I read this, I was under the impression they were; perhaps passive matrix
> screens are and active are not.

I even used a laptop for a Tempest demo in Ross' undergraduate security
course here at Cambridge, because it gave such a clear signal and was
much easier to transport than a CRT.

> (actually, I can totally understand that
> wrt the pulse modulation not present in modern crts)

I added this sentence in the paper only for those who had read the
van Eck paper before, which in this respect is a little bit out-of-date
and does not describe today's VDU technology.

> I had a real bitch of a time finding open source TEMPEST information, which
> is part of why the idea was back-burnered.  I think there is a concerted
> effort on the part of the government to prevent open source discussion of
> the topic, through manipulation of research money, etc.

Same experience here ... :-(

Markus

-- 
Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK
email: mkuhn at acm.org,  home page: <http://www.cl.cam.ac.uk/~mgk25/>