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How Claude's text watermarking works

https://www.anthropic.com/news/claude-text-watermark
33•surprisetalk•1h ago

Comments

whalesalad•48m ago
Seems pretty easy to defeat by running text output through a random reworder process that would effectively repeat the same routine on low-stakes words, replacing them with similar ones. We learned this in high school, jumping through your paper and hitting random words with the thesaurus to 'sound smarter'
yapfrog•38m ago
That will likely make the text output worse and you'll have to fix it yourself. Regardless even if you don't fix it, at that point you're not really using Claude to generate the final output anymore.
whalesalad•22m ago
Seems like claude is already making it worse by choosing a random token that might not be the best one.
nonethewiser•6m ago
The point is if you can trivially change it. This remains to be seen. Its jot very useful if it only detects things that were one shots.
mrcwinn•46m ago
“How does affect Claude’s outputs?”

Is poor proofreading a form of watermarking? Clever, I suppose, but they should consider running posts through Sol for clarity.

nonethewiser•8m ago
Well that gives it authenticity.

As bad as Claude Code’s writing is, it wouldn’t make that mistake.

soupspaces•45m ago
Yesterday https://news.ycombinator.com/item?id=49292932
mlmonkey•45m ago
Can anybody take a body of text and determine if it's from Claude or not? (Or if it's AI-generated or not)?
yapfrog•41m ago
> How do I check if a piece of text was written by Claude?

> We will soon be offering a watermark detection API. We’re in the process of working out the details of its implementation.

Determining whether it's written by Claude will be possible in the future. But unless you know the LLM being used and the company behind that LLM offers a similar API, there's no easy way to tell if it's AI generated in general.

nonethewiser•10m ago
There will be tools to scan across a broad spectrum
jazzpush2•44m ago
Anthropic: doing everything they can to own any output they produce/prevent scrubbing of association for them - except when it comes to the CEO's wife's porn funding attempt from Epstein :D https://www.wsj.com/tech/ai/claude-dario-amodei-wife-anthrop...
absoluteunit1•40m ago
> Google DeepMind tested this impact by serving a model that used watermarking to a portion of their Gemini traffic and comparing thumbs-up and thumbs-down ratings. They found no statistically significant differences from the unwatermarked model. And in a controlled study, human raters comparing watermarked and unwatermarked answers side-by-side saw no difference in quality.

For some reason I had assumed testing this would be more sophisticated than just checking the thumbs up/down stats and user "vibes"

cube00•30m ago
More unannounced testing on paying customers.
baliex•15m ago
Genuine question, how else would they do it? And isn’t this practice the same as basically any agile-developed SaaS?
thevinter•6m ago
I'm not a mathematician but to me it doesn't seem so far-fetched to think that there might exist some mathematical proof that ensures the indistinguishability
cj•9m ago
The only function of the thumbs up/down buttons are to give feedback to Google. As a user it's pretty obvious that's the purpose of the button.
visiondude•30m ago
I’d like to better understand the minimum text length to get a confident result, i would presume it would need to be quite long, perhaps > 1000 words to get an accurate result.
nonethewiser•12m ago
From what I’ve read its closer to 100-300 words. And maybe 500 words to include info identifying the prompter.
jluysvi•29m ago
Opus 5 must be the pilot becuase it's writing style is so grating it has to be intentional. Let's hope they make it more subtle in the future.
nonethewiser•14m ago
It does feel like it comes from somewhere specific. I mean maybe its just a diffuse set of reasons but it feels pretty abrupt.
herywort•13m ago
Watermarking has no impact on style of writing
pr337h4m•28m ago
We are very fortunate open source models have reached parity for virtually all non-coding use cases.
NewsaHackO•21m ago
Do open "source" models have have this watermarking enabled? How do you know?
nonethewiser•16m ago
It doesn't matter if they are watermarked if there is no ability to verify the watermark.
arjie•25m ago
Interesting. Here's the section of the EU Act that mandates this:

> Providers of AI systems, including general-purpose AI systems, generating synthetic audio, image, video or text content, shall ensure that the outputs of the AI system are marked in a machine-readable format and detectable as artificially generated or manipulated. Providers shall ensure their technical solutions are effective, interoperable, robust and reliable as far as this is technically feasible, taking into account the specificities and limitations of various types of content, the costs of implementation and the generally acknowledged state of the art, as may be reflected in relevant technical standards. This obligation shall not apply to the extent the AI systems perform an assistive function for standard editing or do not substantially alter the input data provided by the deployer or the semantics thereof, or where authorised by law to detect, prevent, investigate or prosecute criminal offences.

https://eur-lex.europa.eu/eli/reg/2024/1689/2026-07-27/eng

It definitely makes Pangram's job a bit easier.

johnfn•21m ago
> We will soon be offering a watermark detection API. We’re in the process of working out the details of its implementation.

Dumb question - doesn't this defeat the purpose of a watermark? i.e., anyone who wants to avoid detection can simply run `while (has_watermark(text)) text = slightly_rewrite_with_non_anthropic_llm(text)` until it's gone? I feel I am missing the intent of the watermark if it is so easily defeated.

nonethewiser•19m ago
Yeah kinda. You cant be confident a negative is true.

It doesn’t undermine positives though. That’s just whatever the false positive rate is.

So if it comes back as anthropic generated, it most likely is. If it comes back as non-anthropic generated, we have no idea.

If anthropic didnt make it public there would only be a narrow path for governments or something to make requests. Its kind of fucked either way.

snowe2010•16m ago
I thought the same thing. Maybe they can restrict it so that you can’t run the same text through multiple times with only one word differences. At least from an IP perspective that would start to get really expensive to rotate through IPs to get around a block like that.
pan69•14m ago
Not sure either why they are providing an API to detect either and what you say make sense.

However, if my understanding is correct, the reason for the watermark / detections is that its not directly aimed at end-users, but to be able from them to detect if text was produced by one of their models so they don't use it as input in training data. So, yeah, in that context, not sure why they are announcing this with an ability for anyone to detect if it was produced by one of their models. Also, they are happy to ingest text produced by models they don't own? Maybe someone with more information can elaborate?

efavdb•8m ago
The method of identifying authorship isn’t new. I guess the main new thing here is to ensure Claude has a specified word distribution so you can identify its writing.

https://towardsdatascience.com/text-classification-and-the-b...

himata4113•7m ago
From what I understand when you re-tokenize the output you can simply look at how often certain tokens show up and the position of them, enough of these matches would result it watermarked text.

Let's say we are at token 431 and there is 49% to generate token 1 and 51% to generate token 2, we apply bias to our token 1 which would make it win causing a repeating pattern invisible to the human eye.

Now you apply this to multiple tokens and a reversible source of random you have a pretty strong watermarking system... That is rather annoying to defeat as you essentially have to rewrite most of the text. The alternative is to use a diffusion model and spray some gaps across non-literal information such as ids, links, etc.

omoikane•14m ago
> while (has_watermark(text)) slightly_rewrite...

I understand what you are trying to say but I am not sure any watermark detection API would definitively return a true/false answer, I would have expected something more like a numeric confidence value. I am also not sure if the API would be deterministic.

euio757•12m ago
> anyone who wants to avoid detection can simply run `while (has_watermark(text)) text = slightly_rewrite_with_non_anthropic_llm(text)` until it's gone?

What do you think the pricing per call of "has_watermark(...)" will be?

https://x.com/i/status/2087235360690741690

An important principle: Never pay someone to remove a problem that they themselves created

DonsDiscountGas•7m ago
It's completely pointless without an API, unless you're thinking the API should be private or restricted. The public needs some way of identifying the watermark.

> anybody who wants to avoid detection can just

They can just use a different LLM. By far easier and more reliable than what you're suggesting. This whole watermarking requirement is better then nothing because meant people are profoundly lazy, but yes it is not hard to work around with any effort.

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