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.

How do I retrieve a file from bittorrent with just its hash? Does WebMirror solve that? I’ll have a look at it…

If you sha256sum $file and send that hash to somebody, they can’t download the file from IPFS (unless it’s <2MB IINM), that’s the problem. And it can be any hashing algorithm md5, blake, whatever.

Jottacloud is what I want to use. Unlimited storage for ~100€/month

Close behind is 1fichier for 2€/TB/month or 12€/TB/year, but they are in France and “uptobox” (a similar provider) was shutdown by the US on French soil because they allowed providing links to the files.

You can probably find others in the list of storage systems supported by rclone