Quote from: n0nce on Today at 02:04:25 AM

Weeell, let's take a step back here. First of all, I don't understand what you are trying to prove. That when requesting data from some URL some certain reply comes back?
Even if you were to prove that, the API / backend could always change - so you could at most prove that it did return said data at a certain point in time.
You also don't really need to publish that on the blockchain, instead simply send the proof to the people interested in said proof and call it a day.

Precisely, for the example case I want to prove that the URL contained a specific nonce at a certain point in time, publishing the proof to the blockchain would be the equivalent to timestamping, so that I can't be using a proof from last week to prove that the nonce was present yesterday, even if it is no longer there today.

Quote from: n0nce on Today at 02:04:25 AM

You're also correct in that proving ownership or knowledge of something can be easily done using Zero-Knowledge Proof algorithms and no secure element is needed for that.

I suppose my question is more about what class of computational problems I can expect to have a zero-knowledge proof of knowledge, and how to determine the amount of data necessary to store such a proof.

For example, can you use the same strategy to formulate a zero-knowledge proof for the above example and also to prove that a result of a visual classification problem was calculated using a specific open-source neural net without modification?