Asklemmy

Also read that the keys are stored locally but also somehow stored in the cloud (??),

Which keys? Are they always stored or are they only stored under certain conditions? Are they encrypted as well? End to end encrypted?

which makes it all completely worthless if it is true.

It doesn’t, because what you described above could be fine or could have huge security ramifications. As it is, my guess is that you’re talking about how Signal supports secure value recovery. In that case:

1. The key is used to encrypt your contacts, profile name, group avatars, social graph, etc., but not your messages.
2. Your key is only uploaded to the cloud if you have a recovery PIN or passphrase
3. Your key is encrypted using your PIN or passphrase using techniques (key-stretching, storing in server secure enclaves) that make it more difficult to brute force

The main criticism of this is that you can’t opt out of it without opting out of the Registration Lock, that it necessarily uses the same PIN or passphrase, and that, particularly because it isn’t clear that your PIN/passphrase is used for encryption, users are less likely to use more secure pass phrases here.

But even without the extra steps that we can’t 100% confirm, like the use of the Secure Enclave on servers and so on, this is e2ee, able to be opted out by the user, not able to be used to recover past messages, and not able to be used to decrypt future messages.