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Polarized Screens to Hide Sensitive Data
NiugMan writes "NewScientist.com reports that Iizuka Denki Kogyo, a Tokio-based tech company has developed a monitor which appears to be blank if you stare at it with your eyes. Only by wearing a pair of polarised glasses you see stuff on it. The idea is to protect sensitive data from unauthorised personnel. Please take your special glasses with you when you take a coffee-break."
It can be defeated with 3-d glasses?
How about normal, polarized sunglasses and someone who can rotate their head?
Me thinks someone spent too much on research for this one.
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"Why in the hell is my computer always turned off when I get back from taking a leak?"
"I don't know, Bob. I had to look at it for something, it was off, and I tried to turn it on, but all that happened was that "power" light turned off."
Yeah. Brilliant idea.
Kuhn adds that an opaque shielding device might be simpler way to obstruct prying eyes.
I wonder if he has a patent on this idea. Wouldn't it just be better to have people in, I dunno, offices? You could control entry via special security signatures know as "keys," which would be small metal devices small enough to fit into your hand. Access to data would be protected by an "opaque shielding device" called a wall.
I'll take my consulting check now, please.
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I am an expert in electricity. My father held the chair of applied electricity at the state prision.
Second, how many different polarizations are there ? Last time I studied optics, one pair of glasses will work on any of these monitors (maybe needing some rotation/tilting). Unless you can assure polarizing glasses will always be bright red so you recognize "people with bright red glasses coming near my computer", and you can't assure that - it's quite easy to make polarizing lenses - the protection is senseless.
I can hardly wait until some company buys monitors and glasses to all their employees and then put several monitors in the same room, all people with polarizing glasses, making the whole buy futile. (Hmm, ok, will prevent the floor sweeper from reading your screen. Great.)
As others have pointed out, polarizing filters are so common that there's no security here.
It's like locking your house with a skeleton key.
Why not insert noisy frames between real ones and just synchronize the glasses so that they filter out the garbage frames? Why not just have the screen in the glasses?
I read about this a long, long time ago (I can't remember when, but it is on the order of years). It was a mod that a company was selling for business people's laptops. They'd strip off the polarizing film from the laptop's LCD panel, and then you could only see what was on the screen through polarizing glasses.
;)
I'm not sure whether the glasses required were vertically polarized of horizontally polarized. If they were vertically polarized, anyone with a pair of sunglasses could quite easily read the screen (but wouldn't you look odd wearing sunglasses on a plane while staring at a business person's apparently blank laptop screen).
On the other hand, if the required glasses were horizontally polarized, you'd have to rotate the sunglass lenses 90 degrees (which, since most sunglass lenses do not posess rotational symmetry, would mean you either would have a serious mod coming, or else you'd just have to tip your head 90 degrees... Actually, this might just work, but only if you were pretending to sleep and laying your head on the business person's shoulder, and that's likely to just make them upset.
> The cost of polarized system is too high
> and is certainly not justified.
Actually, all LCD monitors *already* have the capability built in. The way they work is by using the polarization of light. All you have to do to make one of these "secure" panels that can only be viewed through polarized glasses is *remove* the polarizing film from the monitor.
Put simply, it should not be much more expensive to *leave out* part of the panel, eh?
I just love the cost of these monitors ...
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Um, put a polarizing filter on the monitor, add a simple 90 degress polarized light source to the front of the monitor (translucent sheet) put on your polarized glasses and you are set.
Sounds like bad security practices to me
Btw. The gentle fisher folks have been using polarized sunglasses for spotting trout for years
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Smiley or not, that's actually a brilliant idea, that would render all of those sixteen hundred dollar and up monitors (for just 15"--sheesh) useless from a security standpoint.
Wearing polarizing sunglasses and tilting your head would be very conspicuous, to say the least. But polarizing contact lenses would work perfectly in this application. (This 'application' being the misappropriation of sensitive information.) It's not a trivial task to prepare them, but it's certainly not out of reach of a person of above average competence. If a person has naturally dark-coloured eyes, the added shading from the polarizers wouldn't even be apparent.
Need a quick and dirty solution? Look at the reflection of the monitor in a piece of plate glass. A blank acetate sheet will do in a pinch. Reflection off of a clear material will separate the two orthogonal polarization states of light if you adjust your viewing angle correctly. Sure, the information will be backwards, but if you're just feeling a bit nosy, it's no problem. And it doesn't look like you're looking at the screen in that case.
You want to protect sensitive information? Put it behind a wall.
~Idarubicin
Working in the IT Dept. of a bank, I can see how this could possibly appeal to the decision makers in the bank, and the industry at large.
Privacy is big in banking. Bigger than big. There is nothing more important that people's money, and there are enough federal guidelines and regulations on the subject to choke a horse. People can argue about the importance of their kids, cars, and homes, but if a bank employee makes a mistake and suddenly your financial information is stolen or made public, you've got one hell of a lawsuit, and one severely ill person on your hands.
While the technology does seem a bit silly in its inception, and beating this security measure is a moderately difficult at best, what security guard or bank personnel is not going to notice the strange looking individual with 3-D glasses on and a terrible case of tilting-head looking over the shoulder of a CSR or teller.
Of course it's beatable, and of course it's not going to make sense in your average office environment. But I'll tell you right now that there is nothing better than this, that I can think of, that has come along in terms of blocking people from looking over the shoulder of bank employees. Sure there are vertical-blind-like shadded screens, where the information is only viewable when looking directly at the monitor (and we employ those as well), but this again is foilable by a person's mere position. If the employee gets up for coffee, a smoke, whatever, the information the screen is still viewable by anyone with a direct line of sight.
This technology can prevent the average person from seeing what's on an employee's screen. The "average person" is about 95% of all bank customers. The "average person" won't really care how it works, won't want to know why it works, but I'll tell ya, the "average person" will feel a 100 times more confident in his/her financial institutions commitment to security and privacy when using this technology, even if it can be foiled by 3D-glasses or expensive shades.
When you combine this technology with the common sense of "closing all applications when leaving your desk," a financial instutition's employee's desk becomes 10 times safer than it was originally, and that's a big step. I'm certain that the larger financial institutions out there (Citibank, et al) would be glad to show off the new technology and tout about its security, even if it can be foiled by the strange looking man wearing $3 3D glasses.
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I've been meaning to get this on Slashdot for some time now, but I worked on a much more powerful version of such glasses over a year ago at Mitsubishi Electric Research Labs (MERL) in Cambridge, MA, with Researcher William Y. Yerazunis. Here's the technical report if you'd like to see it. We also filed a few patents way back then as well, so I wonder if this work infringes on our own.
We can actually hide secret images within any image or animation you'd like, not just an obvious blank screen. We also designed a cryptographically secure version which isn't cracked by simply having another pair of special glasses (you also need the private key). Check out the paper, it has some image examples (there might be a few technical errors in it that we later fixed but wasn't updated in the paper. I'm not at MERL anymore, so I haven't bothered checking really).
Also, we made a video demo for the conference which our technical report was accepted in paper form (at OzCHI2001). I have that video, and can digitize it if there's enough demand. By the way, while I was testing the glasses, I actually used They Live screenshots so that one could simulate Rowdy Roddy Piper's shock upon seeing the billboards and aliens. Also, we referenced John Carpenter in our paper.
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Second, how many different polarizations are there?
There are more kinds, circular for example. It means the electric field is rotating, either clockwise or counterclockwise.
But that won't work for screens. The liquid crystal will ROTATE a LINEAR polarization but won't reverse a circular polarization. The screen starts with a light source, linear-polarizes it, selectively rotates the polarization, then linear-polarizes again. Depending on the amount of rotation you get more or less light.
This ancient hack consists of taking the final linear polarizer off the front of the screen and wearing it as a pair of glasses. The screen now emits a constant-brightness, varying-LINEAR-polarization light, which isn't translated into variable intensity until it hits the polarized glasses.
But that means that if you get the polarization right you get the image, if you're off by 90 degrees you get a negative image, and at other angles you get an image that has an intended-versus-perceived intensity graph something like a check-mark. Unless you happen to be at the angle where the letters and the background match exactly it's still readable, and if you're at exactly that wrong angle just tilt your head a LITTLE bit and they reappear.
So stock polarizing sunglasses read all these screens, no problem.
If you could come up with a final filter for the screen that converted, say, the vertical component of linearly-polarized light into right-circular and the horizontal into left-circular, you could then use circularly polarized glasses and defeat linearly-polarized. But I don't know of any physical mechanism (let alone one that could be turned into a cheap thin film) that would do this, even for monochrome, let alone the near-octave of light used by color displays or the full-octave for black-and-white.
Even if you DID come up with a circularly-polarized hack you'd only have TWO possibilities for the glasses - and viewing the display with the wrong one would just give you a negative, but readable, image.
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