Because we only know what the client does, and have no clue on the server side of things, allowing Proton to do any manipulations with the data. Not ideal when you consider it for password storage.
Something like Vaultwarden if you care about cloud sync, or KeePassXC if that’s not on your priority list.
if the client is e2ee and you can control that, then why is the server relevant?
Because non-obvious backdoors can be added to the client that break or circumvent encryption (looking at you, xz), stealing all of your passwords, and no one will be able to raise the alarm just by looking at the server code.
Open-source backend allows to generally avoid this situation, while also potentially rendering you able to self-host if you’re paranoid.
and you can control that
Sorry, I meant “assuming one has complete control over the client source” where the remote cannot just change it on you.
