element-hq
Can't restore key backup when key is not encrypted with default 4S key
When restoring with a security phrase, the operation fails with the error message:
Could not enable key backup: Could not read key backup with the given key.
The key is a random long string, and when trying to enter it as a security key, the operation fails as expected with the message "not a base 58 character" or similar.
The account has two 4S keys, one of which is default.
Possibly related https://github.com/vector-im/hydrogen-web/issues/762#issuecomment-1166233069
What is likely happening:
- User bootstraped cross-signing for the first time, using a passphrase
- User bootstraped cross-signing again with the same passphrase, creating a new 4S key and changing the default key. For some reason the backup key is not migrated to the new key
- When logging in in Element, they are asked for the passphrase twice, after which they can correctly restore from backup. Element prompts for the passphrase a second time, likely because of the backup key being encrypted with the old 4S key, for which it doesn't have the passphrase yet.
- When logging in with Hydrogen, it only supports using the default 4S to decrypt the backup key, so it fails.
We should likely adopt a similar behaviour to Element where we can prompt for multiple 4S keys?
How come element does not have this problem them? Is it because when you enter your key that they try to decrypt values with that passphrase/key of all the keys that are found in the account data rather than just the default one?