Legacy cipher is no longer supported

[kylespencer]

Nextcloud Notes (and/or the associated Android app) appears to be generating files using a legacy cipher that Nextcloud no longer supports when server-side encryption is enabled.

After using Notes via both the web and mobile application (with a poor quality Internet connection) some note files are no longer accessible via Nextcloud. Attempts to access or synchronize the affected files (via a device client) fail with the following error:

Legacy cipher is no longer supported!

I have not yet determined the steps to reliably reproduce this problem, but I wanted to share this observation in case others have encountered this problem and can provide more information.

• Notes app version: 4.1.0 (may have also been the immediate prior version)
• Nextcloud version: 27.1.4

I am also posting this issue in nextcloud/notes-android#1955 in case the problem stems from the Android application.

[OffensiveTitle]

I've reproduced this on Nextcloud 28.0.1 using the Nextcloud Notes app 4.1.0.

[OffensiveTitle]

I seemed to have fixed this by running:

sudo -u www-data ./path_to_nextcloud_root/occ encryption:scan:legacy-format
sudo -u www-data ./path_to_nextcloud/occ php trashbin:cleanup --all-users
sudo -u www-data ./path_to_nextcloud_root/occ versions:cleanup

And setting 'encryption.legacy_format_support' => true, in config.php in nextcloud/config (Tested this as of Jan 19, 2024)

Explanation: Legacy cipher is (for some reason?) used by the Nextcloud Notes app, this does not include headers which the new encryption module does; as a result you get the error Legacy cipher is no longer supported!.

sudo -u www-data run the command as your web user (I'm using Debian, so forks like Ubuntu should have the same name).
occ encryption:scan:legacy-format scans your files to find any that do not have proper headers. While running this if anything comes up like:
/your_username/random_file.vXXX does not have a proper header
This means that you have legacy encrypted files.
occ php trashbin:cleanup --all-users this empties the users trashbins which may still hold old legacy files.
occ versions:cleanup this cleans and updates the old legacy files.

Setting encryption.legacy_format_support' => true, in config.php in nextcloud/config adds legacy encryption support back. (Otherwise it's probably best to keep it off)

If I've made a mistake please correct me.

[Croydon]

This still seems to be the case

[joshtrichards]

The Notes app has no awareness of the use of Server Side Encryption. That is abstracted out and provided by Server.

Does it happen when you create new Notes?
What if you create a new text file in Files itself?