Opensource

It's tough. The problem is that, on the tech side, technically, torrents don't have to seed. People have made fake torrent clients that only pretend to seed, but actually only download. The IP's are detected and then banned, but it's a cat and mouse game.

Enforcing it with backups is a similar struggle. There exist paid solutions, that use crypto to pay for decentralized storage. You "rent" out some of your storage, or by some using crypto. Filecoin, sia, storj, and so on.

But these have flaws too. Often, there level of decentralization is questionable, and the maker of the crypto takes a cut, plus there are issues with using a custom crypto coin as well. The coin's value can fluctuate — there are challenges with it simultaneously be an investment, AND a currency, but that's what often happens.

A better solution, is just to trade hard drives with your friends, who you know in person. Or maybe trust online, at least. Just give them an encrypted backup. And then they give you an encrypted backup.

In my opinion "encrypted, decentralized backups", is the kind of problem that is extremely difficult to solve technically, but is trivially solved via touching grass. I don't really like the technical solutions people have presented to this problem, and a local community is a much simpler way to solve these challenges.