October 19th, 2011, 09:41 PM
Increasing Digital Noise..?
Is there a way to increase digital noise imprinted on a digital photograph?
Say some rat is walking around the office. Some employee leaves a sensitive document up on their computer while getting coffee, and the rat snaps a photo of it with his iPhone.
Just wondering if I could increase the noise in the picture, but still have it be readable to the naked eye on the monitor.
October 21st, 2011, 09:59 PM
The first thing you'll want to do is remove the EXIF data. As for noise, programs like GIMP have noise generators which are random enough. Save it to/through a bunch of programs and formats, scale it up and down, and do some crops and what not and you'll probably be good.
As a note: very few adversaries have the capabilities to find out the device that took a picture after you remove the EXIF data and scale it down.
October 21st, 2011, 11:30 PM
If you are on the other side of the street, there is nothing you can do to a display to prevent a readable photo of it other than preventing recording equipment such as cell phones and cameras from entering the facility.
October 22nd, 2011, 02:16 PM
Seems to me that the question is rather like banging your head against a wall and taking aspirin for the headache?
My answer would be:
1. Instant dismissal.
2. Access control and scanning for illicit electronic devices.
Also, if you use a recent version of Windows you can easily bring up a password protected screensaver when you leave your workstation?
Hell, where I worked you had to log out, power off and put the removable HDD into an MoD approved locked cabinet.............. you soon learned to bring a kettle and percolator
I think that I see where the idea has come from?....... I am sure that somewhere (probably on a 486) I have some anti-TEMPEST fonts. These were supposed to thwart TEMPEST remote surveillance of CRT monitors because they were somewhat blurred and apparently very "noisy".
Well, that technology goes back to b&w TVs and reel to reel tape decks, and I do not believe that it is relevant today.
I'll go with ua549, if you can read it, so can a camera.............you have to look at other security measures like restricted access and securing sensitive information when not physically controlled by security cleared personnel.
Last edited by nihil; October 23rd, 2011 at 09:28 PM.
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