# How to prove that node has hash? **URL:** \ **Category:** Help\ **Tags:** js-ipfs, go-ipfs\ **Created:** [December 19, 2018, 5:48pm UTC](https://discuss.ipfs.tech/t/how-to-prove-that-node-has-hash/4494 "2018-12-19T17:48:43Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![nezzard](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ipfs.tech/nezzard/32/2298_2.png) [@nezzard](https://discuss.ipfs.tech/u/nezzard)\ **Post date:** [December 19, 2018, 5:48pm UTC](https://discuss.ipfs.tech/t/how-to-prove-that-node-has-hash/4494/1 "2018-12-19T17:48:43Z")
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? ---
**Author:** ![leerspace](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@leerspace](https://discuss.ipfs.tech/u/leerspace)\ **Post date:** [December 19, 2018, 7:11pm UTC](https://discuss.ipfs.tech/t/how-to-prove-that-node-has-hash/4494/2 "2018-12-19T19:11:15Z")
> [@nezzard](#): > > 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).