[104949] in Cypherpunks
RE: TEMPEST laptops
daemon@ATHENA.MIT.EDU (Trei, Peter)
Mon Nov 2 10:22:59 1998
From: "Trei, Peter" <ptrei@securitydynamics.com>
To: "'Lucky Green'" <shamrock@cypherpunks.to>,
Bill Stewart
<bill.stewart@pobox.com>
Cc: cypherpunks@cyberpass.net
Date: Mon, 2 Nov 1998 10:02:07 -0500
Reply-To: "Trei, Peter" <ptrei@securitydynamics.com>
> -----Original Message-----
> From: Lucky Green [SMTP:shamrock@cypherpunks.to]
> Sent: Sunday, November 01, 1998 8:33 PM
> To: Bill Stewart
> Cc: cypherpunks@cyberpass.net
> Subject: Re: TEMPEST laptops
>
> On Sun, 1 Nov 1998, Bill Stewart wrote:
> [...]
> > Just using a regular laptop isn't enough; I've seen laptops
> > transmit recognizable images to a television (though I was probably
> > using AC power rather than batteries, and may or may not have had
> > the display mode set to LCD-and-monitor.)
>
> Thanks for touching on the popuar myth that laptops radiate less than
> CRT's. Many laptops in fact radiate more compromising emissions than
> CRT's. Ross Anderson does his van Eck demos to undergrads using a laptop,
> because it works so much better than CRT's.
>
> -- Lucky Green <shamrock@cypherpunks.to> PGP v5 encrypted email preferred.
Nearly all laptops have a built-in video port, for connection
to an external monitor. This is often poorly shielded (usually
just a plastic plug). I'd be curious to know how much the
radiation from this port could be attenuated by (1) a metal
plug contacting the laptop's ground plane, and (2) removing
all the video-port specific circuitry (major surgery for a
laptop :-( ).
Peter Trei
