Hi Everyone,
If you have been following the news you would know that Egyptians raided State Security's buildings in different cities. Some people have taken printed documents with them and started publishing information online.
I'm very suspicious of two documents in particular that claim to be meeting minutes by state security officials planning terrorist attacks on churches in Egypt and the notorious Sharm el Sheikh attack back in 2005. For obvious reasons, why in the world would state security document something like this and this leads me to the idea that these documents might be fake.
All I have are the pictures that have been posted online, and I have several questions
1.) How would you go about to try and identify characteristics in the image that prove that this was something photoshopped? (just black/white image of a scanned document).
2.) Are there any applications that you can use that help in the process?
3.) Is it valid to try and conduct a 'visual' examination on a photo that has been uploaded on facebook, do you know of any similar cases? (I know facebook decreases the resolution so it might interfere with how things appear).
I can not contribute much to answering your question. I do have one observation though.
You assume that they took genuine documents and photoshopped them. There are other options, just as possible in my opinion.
They could have been electronically created documents, forged from the get go. (example, they created a word document and turned it into a image)
They could actual documents that were forged, and then scanned.
They could, of course, also be legitimate. Just because they are doing something 'top secret' does not mean there won't be a record of it. It just means the record is much, much more difficult to get to.
All of the above conditions would make forensic analysis of the images fail to provide evidence of photo manipulation.
Yep. If you know how to use GIMP, it's pretty handy for analysing images. Changing the colour/light levels, removing layers and applying filters can reveal a lot about an image, and if anything was added to the images you're looking at, it'll show up. I've seen GIMP used for hiding and revealing content that beneath several layers.
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I suppose you could also try comparing the date on the scanned images with the creation date of the file. That should indicate whether it was altered and when.
Why would you assume that the documents needed to be faked via Photoshop? If the source is scanned images, then the documents could have been faked using something as simple as a word processor.
I would be hesitant to draw any conclusions based upon documents downloaded from the Web, especially if you don't have the source material.
But, this is speaking from the limited information posted, here.
Maybe this article would help - It's from "Problem of Forensic Sciences" magazine, 03/2011
DETERMINATION OF THE GENERATION OF PHOTOCOPIES USING THE IMAGE PROCESSING TECHNIQUE
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We're not ruling out that the documents could have been forged before being scanned. However, I'm just curious to see who attempted to spread false (if it is false) information. If it has been photoshopped, then that would mean the culprit could be the user that claims to have the original document, scanned it and published it.
If we can prove that the image has not been photoshopped, then that would mean a further analysis on the original document is needed, and could lead to the finding that state security officials have created these fake documents. Otherwise, these documents could be true.
It's just me thinking out loud, and wanted to see other people's opinion. Wanted to see if other people have worked in cases that involved something similar. I already knew that working off an uploaded image on facebook is probably a long shot but no harm in asking anyway.
Yep. If you know how to use GIMP, it's pretty handy for analysing images. Changing the colour/light levels, removing layers and applying filters can reveal a lot about an image, and if anything was added to the images you're looking at, it'll show up. I've seen GIMP used for hiding and revealing content that beneath several layers.
Forgive me, I am ignorant about this, and have never done picture analysis before, although the idea fascinates me. Would you be so kind as to go into a little more depth as to how to do this ? A short tutorial perhaps ?
Thanks.
azrael, I also found this site which I think is very interesting.
http//errorlevelanalysis.com/
I love GIMP, and use it for my photography all the time.
I am not sure how one would remove "layers" (as GIMP calls layers) within a PNG or JPG image, but definitely playing with Colorize, Levels, Curve, Posterize, splitting color channels, and similar under Colors menu would be an good start.
I usually look for edges, hasty blending, lighting and shadow discrepancies, error distribution or error level analysis (specs, and camera pattern), color channel edges, etc.
You can start by reading "Adobe Photoshop Forensics" by Cynthia Baron.
I think I remember this being on the news. I forget if it was Egypt but it was a Middle Eastern country. Obama was in the picture and if I remember correctly he was leading a pack of 4 others. The second altered pic showed Obama in the back.
I don't doubt this happens everywhere. China got busted using a clip from Top Gun in one of their military videos showing one their planes shooting down another one.
I think it boils down to a Government feeling insecure about themselves.