Isn't this already solved by watermarking?
This page said they would provide an API to check whether a given text has the watermark for a Claude model:
Watermarking checks whether a _specific text_ came from a provider.
PI checks that the text (that you already know came from the provider) was produced with _a specific set of weights_.
PI is mainly useful for AI supply-chain security.
SynthID-Text paper: https://www.nature.com/articles/s41586-024-08025-4
- it only gives a high probability that the text was outputted from the model, whereas a crytographic proof is computationally infeasible to forge
- it cannot be traced back to the input. You could "wash" the output from one model into another and it would be watermarked by the latter. With the crytographic proof, if you have the input, output, and "commitment", you can verify your exact input was processed by the model (or so the model provider says).