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Many buildings house classified or confidential documents. Many of these documents are accesed by computer. Many of these computers are visible through various windows in the building. The screens will often show up through even tint or mirroring, simply because they are brighter than the outside
environment.
Problem:
A dedicated espionage agent (corporate or national) could find someplace to observe these computers and photograph the screens.
Solution:
Since most of the screens are LCD, and thus polarized anyway, simply tint the windows with a 90 degree polarization, such that the screens do not show out at all.
Anton Piller order
http://en.wikipedia.../Anton_Piller_order
[normzone, Nov 05 2009]
Van Eck phreaking
http://en.wikipedia...i/Van_Eck_phreaking
Monitors close to walls can be read from the other side. The required equipment for espionage was constructed in a university lab for less than 2000 US dollars. [normzone, Nov 05 2009]
Academic project on reflection capture, including eye
http://www.infsec.c...ojects/reflections/
"Capturing reflections from the eye is a much more challenging task due to the more extreme curvature of the eye, resulting in much smaller and less bright images. Additionally, the subconscious movement of the eye causes additional blurring. However, using more evolved equipment, in particular a more sensitive camera and a high-quality telescope, and additional post-processing, the following reflections can be captured." [jutta, Nov 06 2009]
http://xkcd.com/326/
[hippo, Nov 06 2009]
[link]
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A very neat solution to a problem that doesn't really exist. |
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// A very neat solution to a problem that doesn't really exist. // |
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... and therefore highly bunworthy. [+] |
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I have not been able to determine if LCD polarization is standard. I would assume it's at least standard with a manufacturer, so it should be possible to specify monitors that would work with a given window polarization. |
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[UB] That did occur to me, but it requires people to work in a certain orientation. This has the advantage of achieving the same thing and allowing layout flexibility. |
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(I also think high security buildings are built without windows for this reason, but this would mostly be for corporate proprietary information in any given office park or downtown high-rise.) |
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Hmmm. I know squat about counter espionage but it would seem to me that a screen shot might be able to be taken in the relfection of the users pupil or glasses from a powerful enough telescope.
How would polarizing the windows effect this inverted image? |
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// with foreign military and government figures // |
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What most people don't realise is that there's little point in security if you ARE "High authority". |
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Security is mostly about keeping stuff from regulatory authorities..... if you're not answerable to anyone, why worry ? |
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A reflected image should retain polarization. |
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//a screen shot might be able to be taken in the relfection of the users pupil // |
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I call bullshit. That's movie mumbo-jumbo, and I'll eat my hat if anyone ever does it in real life. |
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[terms of wager - using a telescope in one building to take a screenshot via pupil reflection from a person in an adjacent building, of what that person has displayed on their screen. Must be of text-reading resolution.] |
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I shall take a Nikon D3x with a 600mm f/4 please, maybe with a 2x teleconverter. Should provide me with a reasonable image, if not, there's always upscaling software out there that should produce a perfectly legible image.
What do you mean you aren't buying me the equipment? |
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Pupil doesn't seem likely, but glasses might be, door glass or
something similar probably is, if you're unfortunate enough
to be in just the wrong spot. |
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That is quite the tale UnaBubba. |
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I thought I had the whole affect/effect thing down pat; affect is a mannerism like speaking with a fake accent, and effect is everything else.
<heads to dictionary.com> |
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Once again, [UB] cleverly effects the correction of another's grammar (and while we're on the subject, see link). |
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Ah XKCD, is there a situation they don't have a comic for? |
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[+] Or tint them the other way if your the espionage
agency. |
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[+] This is what I too had thought of some time back.
This will darken the windows though, reducing sunlight. |
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I would also suggest covering the lightbulbs with polarized filter, thus illuminating the insides with a polarized light. Thus, with polarized windows in between, outsiders wont be able to see a thing on the inside. |
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Nice idea, but one-way glass (via other methods) is already baked. The NSA 'cube' is clad in it for the express purpose you mention. |
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why not just make windows out of active LCD's like welding helmets. IF you want to show classified material just tint the windows to black |
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My automatic welding hood has a 2.5" x 4" LCD shade and
cost $300. A pane of LCD glass ten times that size would
still be
a very small window for three grand. (before anyone comes
back at me with contradictory figures, my hood is a top-of-
the-line Miller; I know there are much cheaper ones, but
my point still stands) |
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I'm pretty sure that the welding mask is arbitrarily
overpriced. |
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