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this sentence in the paper only for those who had read the van Eck paper before, which in this respect is a little bit out-of-date and does not describe today's VDU technology.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