A tool to show what has been done to the image. For example to show that a picture of a snow leopard wasn’t altered in post.
Sample https://verify.contentauthenticity.org/
Open source https://opensource.contentauthenticity.org/
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Isn’t darktable not all about altering images in post 
. I do not really understand the advantage of this idea.
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If I understand it right it shows the path that was taken for the image, see the verify link.
The photographer can still choose not to use CAI or to arrange the scene before taking the picture,
For example seven pictures of a snow leopard. With CAI it would for example be easy to see that 2, 4, 5 and probably 7 were altered and in what way. But it would also show that 1, 3 and 6 where taken of something that existed in front of the camera. Zoo or in the mountains, who knows.
https://hionlife.se/package/fotoresa-snoleoparder-ladakh/
https://hionlife.se/wp-content/uploads/2018/05/snowleopard1.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard2.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard3.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard4.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard5.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard6.jpg
https://hionlife.se/wp-content/uploads/2018/05/snowleopard7.jpg
For the images above one tool I used was Exiftool and exiftool -all snowleopard*.jpg or exiftool -documentancestors snowleopard*.jpg
The tag document ancestors seems to be a copy/paste tag.
I also used darktable to brighten the pictures. Nr 2 and 5 stood out.
Running exiftool -documentancestors *.jpg for the images at https://kittiyapawlowski.com/ also showed copy/paste for some of the images, but not what was copied/pasted. And that is what I guess CAI could be help, not as a complete solution but to make things more transparent.
Well, the catch is that it only works for images that use the technology.
And it looks easy enough to get credentials for an already altered image: just enter it in the system as a new image. It will get the “content authenticity” seal showing no alterations in post, which is true as far as it goes…
Given how carefully most of the public look at such things, such a use of this system may actually be worse than a “non-certified” image.
And there seems to be a kind of centralised “clearing house” involved as well, they seemed not too clear about that.
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That would be arranging the scene before taking the picture. Taking a picture of a picture. I would compare this feature as an alternative to showing the raw file.
Sony A7 IV, Leica M11 and Nikon Z9 seem to get support for CAI.
Canon joined last month.
There have been many attempts before but they have been unsuccessfully. Canon released Truthmark that now is gone and before that the Canon Original Data Security was cracked Canon “Original Data Security” Cracked, Rendered Useless
After the Canon crack the same happend to Nikon Nikon Image Authentication System Cracked Just Months After Canon's | PetaPixel
For my kind photography I see no advantage. But others might have different views.
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I take pictures for news, but have never been questioned about my pictures. A thing I think about is what blurring registration numbers or faces will look like with CAI. Will the unblurred picture be visible if CAI is used?
I define photography as the art of manipulating light to capture a three-dimensional moving world as a two-dimensional still image. We manipulate by many means including the choice of aperture, shutter speed, focal length of lens, position of camera, choice of film brand (if shot on film) and of course post shooting edits.
Since Darktable is 100% about manipulation I don’t see how this “content authenticity” can ever be part of the program. Even if you use the out of camera JPG it has been manipulated according to the black box programming of the camera manufacturer.
The closest you can get to content authenticity is shooting color slide film and leave the digital camera at home. Thanks for your post here and no offence meant by my comments.
Seems not to be like that at all, does it? Content Credentials
It seems more like darktable’s open pixelpipe compared to the closed ones in Capture one/Lightroom. Visible for the user to see what steps have been made and in what order. Manipulate as much as you want but it will be transparent.
The “content credentials” only show which images were used as the basis for the current image. So if the lowest landscape image with “credentials” had those removed, you’d never know that a person had been removed from that image.
And none of the images show any edit information, which would be what dt stores in the metadata. Otoh, that edit information is rather useless without the program that generated it…
So I don’t see what those “content credentials” add for an image where the history does not start from raw files.
This?
About raw files, let’s see how CAI envelopes. All the other attempts before have failed, but this time there are more companies involved than just a single camera company.
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First camera with CAI Leica announces M11-P with Content Authenticity Initiative metadata recording: Digital Photography Review
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USD 9195??? Gulp.
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A car or a camera? Easy choice.
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I don’t drive cars. Never did
.
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Not everyone can live such a luxurious life.
I drive them, but never owned one myself.
A reasonable compromise me thinks.
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You mean driving bike or train is luxury? It’s just my personal way.
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Yes. In a world where public transport and bike paths are considered side-projects, yes.
Personally I would even prefer to walk, because you get to see so much more.
Bikes and trains are a second best, cars are sadly still a neccessity for a lot of circumstances.
Sorry for de-railing (pun intended) the thread.
@Peter I get back to your original question…
Indeed I personally feel that in our present world replete with fake news and AI-generated ‘inventions’, having a way th check the origin of a picture (even reframed/processed, as the CP2PA allows) will be extremely interesting.
I see closed-source softwares definitely startng with this (Adobe, of course…) : now if Darktable was the first open-source to offer it, this would definitely raise professional interest IMHO…
There is an introductory video around a Leica camera that sounds very convincing here…
Hervé
Certification already exists, for example, for digitally signed contracts, documents and PDFs, and for identity authentication. I am sure the “clearing house” organizations responsible for administrating could extend their services to photography. However, that would add a degree of oversight most would not welcome with open arms: too much licencing 
and surveillance 
.
BTW, @Herve5 welcome to the forum.
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