You typically want a slightly-more-elaborate approach than just handing the network a hash and then getting a file.

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Blake 3 supports verified streaming as it is built upon merkle trees as you described. So is IPFS. As I mentioned, IPFS hashes are that of the tree, not the file contents themselves, but that doesn’t help when you have a SHA256 sum of a file and want to download it. Maybe there are networks that map the SHA256 sum to a blake3 sum, an IPFS CID, or even an HTTP URI, but I don’t know of one, hence the question here.

BitTorrent and Hyphanet have mechanisms that do this.

Do you know of a way to exploit that? A library maybe?

It’s quite simple: I want to retrieveFile(fileHash) where fileHash is the output of md5sum $file or sha256sum $file, or whatever other hashing algorithm exists.

I’m not sure what your concern is. I’d basically like to call a function retrieveFile(fileHash) and get bytes back. Or call retrieveFileLocations(fileHash) and get URIs back to where the file can be downloaded. Also, it’ll be opensource, so nothing to reverse engineer.