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Check if a file was made with Claude

claude.com

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Re: Check if a file was made with Claude

#111

Post by [deleted] »

Retr0id wrote: post #109
panarky wrote: post #96

Earlier quoted context omitted.

Just because you can imagine how a thing could theoretically be broken does not make it broken. It's like saying a prisoner has the same freedoms as everyone else because he could theoretically escape.

It's not a theory, I've done it. Here's a cryptographically signed + timestamped photo of me winning the lottery: https://verify.contentauthenticity.org/?source=https%3A%2F%2... Would you like to buy my winning ticket from me? (Compare against winning numbers and draw timestamp at https://www.euro-millions.com/results/28-08-2026 )

[deleted]

Re: Check if a file was made with Claude

#112

Post by [deleted] »

Retr0id wrote: post #109
panarky wrote: post #96

Earlier quoted context omitted.

Just because you can imagine how a thing could theoretically be broken does not make it broken. It's like saying a prisoner has the same freedoms as everyone else because he could theoretically escape.

It's not a theory, I've done it. Here's a cryptographically signed + timestamped photo of me winning the lottery: https://verify.contentauthenticity.org/?source=https%3A%2F%2... Would you like to buy my winning ticket from me? (Compare against winning numbers and draw timestamp at https://www.euro-millions.com/results/28-08-2026 )

[deleted]

Re: Check if a file was made with Claude

#113

Post by chrisra »

AareyBaba wrote: post #103
bilalq wrote: post #100

Earlier quoted context omitted.

There's no way text watermarking isn't causing a degradation in writing quality.

Text watermarking will surely cause a degradation in quality writing. There's is no text watermarking that doesn't cause a decline in writing quality. Writing quality will surely deteriorate if text watermarking is implemented.

Maybe this is silly: what about zero-width spaces or other hidden characters? Add them in post-processing, and the response quality doesn't degrade (though rendering etc. might be wonky).

Re: Check if a file was made with Claude

#114

Post by throwuxiytayq »

chrisra wrote: post #113
AareyBaba wrote: post #103

Earlier quoted context omitted.

Text watermarking will surely cause a degradation in quality writing. There's is no text watermarking that doesn't cause a decline in writing quality. Writing quality will surely deteriorate if text watermarking is implemented.

Maybe this is silly: what about zero-width spaces or other hidden characters? Add them in post-processing, and the response quality doesn't degrade (though rendering etc. might be wonky).

Yes, it is silly. Stripping these is about as trivial as removing "this post was written by Claude" appended in plaintext. You could make a clipboard monitor that does this as soon as you CTRL+C, it's a 1-shot prompt. Not to mention that these wonky Unicode chars will break in every other program.

Stripping Anthropic's watermarking, however, is more difficult - probably about 2 prompts.

Re: Check if a file was made with Claude

#115

Post by ulrischa »

coffeecoders wrote: post #46

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.

For removing cspa you can use https://metastripper.devkram.de/

Re: Check if a file was made with Claude

#116

Post by roosterIllusi0n »

bilalq wrote: post #100
mhitza wrote: post #33

Earlier quoted context omitted.

That is where their responsibility ends in terms of the EU AI Act. And that is fine and how it should be, no secret watermarks.

There's no way text watermarking isn't causing a degradation in writing quality.

The real problem is false positives. One false positives is enough to make the whole thing dangerous. The results can't really be acted upon without risking defamation. If you admit that you redistributed someone else's copyrighted work to an AI company that never forgets, it's an admission of distributing copyrighted works.

The law should have at the very least required offline validation tools that cannot track or retain a copy of the documents being checked.

Re: Check if a file was made with Claude

#117

Post by Dylan16807 »

bilalq wrote: post #100
mhitza wrote: post #33

Earlier quoted context omitted.

That is where their responsibility ends in terms of the EU AI Act. And that is fine and how it should be, no secret watermarks.

There's no way text watermarking isn't causing a degradation in writing quality.

A lot of random-ish numbers go into LLM output and there's a lot of room to hide signals in random-ish numbers.

Re: Check if a file was made with Claude

#119

Post by fn-mote »

sleepybrett wrote: post #102
AmazingTurtle wrote: post #41

Earlier quoted context omitted.

Well, guess they are just trying to conform all the weird EU checkmarks

I'm not sure that 'preventing ai-generated fraud' is really a 'weird checkmark'

If watermarking of any kind were actually going to prevent ai-generated “fraud” (or even ai being used as part of a scam), it would have more support on HN.

This kind of metadata injection increases surveillance without providing a meaningful deterrent.

Re: Check if a file was made with Claude

#120

Post by fn-mote »

roosterIllusi0n wrote: post #116
bilalq wrote: post #100

Earlier quoted context omitted.

There's no way text watermarking isn't causing a degradation in writing quality.

The real problem is false positives. One false positives is enough to make the whole thing dangerous. The results can't really be acted upon without risking defamation. If you admit that you redistributed someone else's copyrighted work to an AI company that never forgets, it's an admission of distributing copyrighted works. The law should have at the very least required offline validation tools that cannot track or…

> offline validation tools

As soon as the validator is available without a rate-limit, just apply input fuzzing to defeat it.

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