Comments

videoITguy wrote on 8/11/2014, 3:03 PM
Well your question begs a lot of questions - for example how did you get TO the word forensic in the discussion?
Are you talking about?
1) a super over an image?
2) an imprint at time of photographic exposure -like time and date in digital photo image?
3)Exif or metadata about an image form?
4)copyright process over image distribution?
Chienworks wrote on 8/11/2014, 5:51 PM
The usual process involves embedding a specific distortion of pixels in the image itself that isn't visible because it blends in with the compression artifacts, but can be decoded to show your watermark ID number. Theoretically this watermark remains even if the image is heavily modified or edited. The idea is that in court the evidence can be extracted (hence the term 'forensic') from the image to prove that you originally produced the image in question, and most likely the perps trying to steal it didn't even know the watermark was there.

I had a plugin for my photo editing software that did this. I imagine the same technology could be used with any still or video format that used DCT compression (like JPEG/MPEG). On the other hand, i don't know that enough people ever used the concept for it to gain any traction or in fact if anyone ever produced 3rd party decoder software.
smhontz wrote on 8/11/2014, 9:56 PM
Digimarc is a company that supplies products that do this. I used to have their plugin for PhotoShop.
YesMaestro wrote on 8/12/2014, 12:49 PM
Kelly is correct. The client actually used the term forensic. Apparently they are going to be doing some stuff with the government and that's what is required.
Paul
johnmeyer wrote on 8/12/2014, 4:04 PM
I got exposed to this when my son briefly got interested in cryptography about a decade ago. There is readily available software that will embed almost any information you want, into almost any type of file, without making any visible change to the content. Here is one of thousands of pages that will give you an idea of what can be done:

Geek to Live: Hide data in files with easy steganography tools

It is actually pretty scary, when you consider how this can be used for nefarious purposes. If someone were trying to hide information, I think this might be harder to detect than if they encrypted it, because the act of encryption calls attention to itself. By contrast, an image (or video) that has been altered with one of these steganography tools will look just the same as a normal image.