Document user key draw backs (SSE) #14086
Description
One suggestion from my side. We should mention that user keys have some draw backs which can easily irritate users.
A example I use all the time: Think about a group share, the moment you share a file with a group Nextcloud will take the public keys of all group members and encrypt the file-key with it. With large groups this can have a (huge) performance impact. If a admin adds later additional users to the group they will see the file shared with the group but they will not be able to decrypt it because they where not part of the group when the file-key was encrypted. This can lead to a lot of confusion and 1st level support request like "i can't open a file shared with me", "nextcloud is broken", etc.
Originally posted by @schiessle in #13754 (comment)