I mean by this, is there any website that with one sign up would allow you to have a matrix account, lemmy account, mastodon account, etc. If it couldn’t be done with just one url it could be made a thing where it would be service.website.tld (so an example would be lemmy.myreallycool.website). Is there anything that already exists like this? I think it would be really cool to just have one home server for everything that you need, and to also have the same identity on all platforms. Another actual practical application of this I can think of is if you want to message someone you know from lemmy but on matrix you could just change the domain (ex: @[email protected] to @[email protected]) or something like that. I know that one of the big appeals of the fediverse is that the accounts are interoperable but I still end up using a different account for my mastodon and lemmy accounts for example. I’m genuinely interested in something like this as I think this would be a really cool idea.
As pretty as that would be it has its problems. For this to work you need an authentication service. If you use that service for everything then your accounts are linked to this auth provider and you get a problem if that service goes down. You create a single point of failure.
That being said matrix and mastodon support oauth providers. So it is possible to have unified authentication provider for these two. Lemmy doesn’t support this yet.
You can make it just be a private key, where you sign a message with it to log in. The service just needs to know your public key
The problem is not the data. Only the central nature and the dependency on a central point.
You should only need one key to log in everywhere, even if the servers are different