Transition to New Encryption Schemes

Problem:

When a new CryptPad versions introduces new encryption scheme, old documents are not updated to this.

Consequences:

If a vulnerability in the encryption scheme is discovered, old documents can not be protected other than being destroyed. To keep the content, users would need to manually export and import it.

Suggestions:

Implement an upgrade mechanism to the latest encryption scheme that can be activated by users. Ideally, the old links are still valid. To achieve this, the new keys can be generated from the same seed as the old ones and the old URL can redirect to the new one.

Drawbacks:

Users might get confused, and old links may be broken after the upgrade.