Thursday, September 29, 2005

Remote surveilance of CRT's and LCD's

Saw an episode of Numb3rs last night, it included the remote surveilance of a computer LCD screen.

No while the monitoring of CRTs is well known (The US DoD first talked about it in 1947!
ARC Search Results: Details pitty they haven't digitised this!) I hadn't heard of it being extended to LCDs yet.

OK, so I'm not security guru (I'm supposed to be developing most of the time), but I still hadn't come across this.

TEMPEST (see above ARC link and here) discussions mention that some LCDs do intefere with TV reception, leading to the conclusion that there might be something readable there... See here [first of three myths], here, here,

However you can get TEMPEST compliant LCDs
here, here, here and even a whole range of computer equipment here.

But no sign of a device to remotely monitor LCDs yet...

This is as close as I've gotten. It mentions the CEI Tempest Receiving System, but all the pics are long gone and no mention of LCD support. But it does mention using telescopes to look at reflections... or even the modulation of the power LED on a montor!

Did just find this 2003 paper
, so it is possible, and this guy has done it, but it's not the LCD screen that's being snooped on, it's the cable connecting the graphics card and the LCD! [in this case on a laptop]

I wonder if anyone has done any comparisons on the different types of graphics card and monitor/LCD connections? (DVI-Analog, DVI-Digital, standard PC[?], Mac, Sun...)

Very interesting field. Far more intreaging than the cracking of Excel passwords that I did at work today...

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