Operating system
macOS
Joplin version
3.6.15
Desktop version info
Joplin 3.6.15 (prod, darwin)
Device: darwin, Apple M1
Client ID: 8a91d26b63c3470e9ac34d57b1fd87c5
Sync Version: 3
Profile Version: 49
Keychain Supported: Yes
Alternative instance ID: -
Sync target: (None)
Editor: Markdown
Revision: c615726
Backup: 1.5.1
Freehand Drawing: 4.3.0
Simple Highlighter: 1.0.0
Suitcase: 0.5.0
Table Formatter Plugin: 1.2.1
What issue do you have?
This is actually about passwords. I want to start using Joplin Cloud but I recently lost some data using Syncthing (nothing in Joplin) and it has me afraid to make the move. I backup to Time Machine sporadically and a daily backup of Joplin to iCloud with the built-in plugin. My concern with enabling E2EE is that the Time Machine and iCloud backups will also be encrypted, so any problems, including foolish mistakes, would result in no access to any notes. Is it possible to have notes on my computer unencrypted but still have encryption on Joplin Cloud and other computers that I sync it to?
That is how E2EE actually works.
TL:DR
With Joplin the End To End Encryption (E2EE) protects your note data on third-party networks and storage services. Locally, on your computer, it is not encrypted.
Explanation
End To End Encryption (E2EE) is a method of encrypting your note data as it travels between Joplin clients. The clients are the "Ends" in "End To End". The data is encrypted for the entire journey from "End" to "End" or client to client.
Without E2EE your note data leaves your computer and travels to the sync server protected by HTTPS (hopefully) where it is stored for your other Joplin clients to download. On the sync server it has no protection other than the promises provided by whoever maintains that server. It is possible for them to snoop on the data they are storing for you. They may also lose your unencrypted data if they are compromised.
With E2EE enabled your note data is also encrypted by the Joplin client as it leaves your computer. When travelling to the sync server the data is protected by HTTPS AND E2EE. When the data is stored on the sync server it is still protected by E2EE. It is not possible for whoever maintains the sync server to snoop on your data as they do not have the E2EE key. If the server is compromised the stolen note data will still be encrypted.
When a Joplin client downloads the E2EE data from the sync server it decrypts it using the E2EE key and stores the unencrypted data locally.
OFFTOPIC, but thanks for that excellent and illustrative explanation of E2EE with Joplin @dpoulton !
Thanks @dpoulton for clarifying this!