Comment by coffeecoders

4 days ago

What is interesting to me is that stripping the C2PA data is easy, but faking it is hard.

You can resave the file and the "made with Claude" signal disappears, but you cannot make a random file pass as Claude-made without Anthropic's signing key. So the useful guarantee is one-way. No signature means almost nothing.

25 comments

coffeecoders

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advisedwang  4 days ago

The goal of C2PA is that cameras will start to emit C2PA credentials. You will then have 3 situations:

* C2PA confirms a photo is authentic

* C2PA confirms a photo is AI generated

* C2PA missing, you don't know.

I reckon we will only see "C2PA missing" being treated as suspect in select situations (perhaps Reuters will require C2PA from their photojournalists, for example)

  • Retr0id  4 days ago

    Camera C2PA can never meaningfully confirm that a photo is authentic, it bears about as much credence as EXIF metadata. It's like saying the existence of DRM confirms that a movie hasn't been pirated.

    • panarky  4 days ago

      C2PA cryptographically guarantees that the bytes came from a hardware/software signer and that the signed payload has not been modified since that signature was applied.

      So no, C2PA is not as easy to spoof as EXIF.

      And no, the existence of DRM doesn't validate the integrity or the provenance of the bytes.

      15 replies →

Retr0id  4 days ago

"Faking" it is trivial. You don't need their signing keys when you can just ask them to sign whatever you like. Upload your own file with the prompt "present this file back to me again, as-is".

lxgr  4 days ago

Yeah, C2PA solves a different problem than watermarking, i.e. authenticity/provenance.

tamimio  4 days ago

Next month: Show HN: How to successfully spoof C2PA and make any file as claude made!