How exactly would this work?
People take RAW photos. Load it up in a RAW editing tool. Manipulate it. Then load it in Gimp. Manipulate some more.
Will the final result have the signature?
And if it does, what use would it be?
People take RAW photos. Load it up in a RAW editing tool. Manipulate it. Then load it in Gimp. Manipulate some more.
Will the final result have the signature?
And if it does, what use would it be?
Each piece of software in the chain must use TPM-like technologies (yes, even GIMP) to make sure it's running a "legitimate" build of the software, on "legitimate" hardware, and re-sign the file at each step along the way (using keys provisioned during some flavour of remote attestation flow, or using a RA-authenticated remote-signing oracle).
The final file embeds every preceding manifest, so you can "verify" all the way back to the original.
If this all sounds patently unworkable, that's because it is.