But up to now, I was not able to get it working.
Is there any documentation on that (that I havn’t found yet)?
I enabled e2ee for my test user, set up passphrase, encrypted a folder and shared it (user1 to user 2).
On (desktop, mac os) client of user2 I get the error message that the encryption information is missing and therefore synchronisation fails.
No luck either with v27.1.0. and desktop client 3.9.0 for Debian.
I have tried to:
encrypt an empty folder then share it with internal user (who has their E2EE enabled) and put a file in it: the recipient receives an encrypted file;
encrypt an empty folder then share it with internal user (who has their E2EE enabled), who then tries to put a file in the folder shared with him: actually the file cannot be pasted in the shared encrypted folder (at least in the Android app);
share an empty folder and encrypt it from KDE Dolphin’s contextual menu: Error 404 to the request PUT https://mycloud.com/ocs/v2.php/apps/end_to_end_encryption/api/v1/encrypted/00000519;
share an empty folder from Android app (which then hides “define as encrypted” options), then have the recipient encrypt the folder (from KDE Dolphin’s contextual menu): error message when trying to paste a file in the folder on the folder’s owner’s android app side, but the file is however pasted unencrypted but not shared, with Desktop app showing a sync error message like “File <name_of_file> cannot be downloaded because the encryption information is missing”. However, when the “recipient” pastes another file in that folder in KDE Dolphin, that new file is shared encrypted (and cannot be decrypted in the first user’s Android app).
I have been sad for at least 3 years to see the E2EE folder sharing advertised as “production-ready” but not actually working. Still relying on wonky scripts involving gocryptfs/cppcryptfs (or Cryptomator when speed is not an issue), and still saying my clients “sadly, there is no open source collaborative solution natively offering E2EE yet”.
Same problem under Windows. E2EE works fine for a single user but sharing does still not work with NC 27 and client 3.9.
I ended up creating a workaround by creating a special user for end-to-end encryption and in the security settings of this user I added an app token for each realworld user, so that I can revoke access for a certain persons later when needed. However, this is a really ugly method with lots of restrictions and also some security concerns. Although it’s said that those tokens can be only used in the Nextcloud client, I fear that it might be somehow possible to access the web interface and change the user password or add additional app tokens.
So I’m still hoping for a real E2EE sharing solution.