How to prove that node has hash?

Hi, i’,m trying to implement reward based on hosting file in ipfs.
I’m looked all of API, but can’t find any command, with which i can check if remote node has pinned file or caт provide it.

As i could understand by reading this forum, that findprovs can show info about nodes, but, this list updating ~24 hours, so it’s not solution to the proble.

I Thought about some crypto functions with keys, to prove, but can’t finish this idea.

Pls if someone know about some API or maybe any ideas how can i prove that node has file?

The naïve approach would be to request the hash from the node and check that it sent you the correct content. If you’re looking for a cryptographic method built into IPFS itself where an untrusted peer can prove possession of a hash’s content without just sending the entire hash so you can verify it, I’m 99.99987% sure you’re not going to find something already implemented (and I think this is related to the proof of replication that filecoin is trying to solve, though I don’t know if they’ve figured this out yet).