feat: Add documentation about e2ee

Signed-off-by: Louis Chemineau <[email protected]>

Author: artonge

Diff for: user_manual/files/index.rst

@@ -10,11 +10,12 @@ Files & synchronization
    deleted_file_management
    desktop_mobile_sync
    encrypting_files
+   using_e2ee
    sharing
    file_drop
    large_file_upload
    quota
    version_control
    projects
    transfer_ownership
-   federated_cloud_sharing 
+   federated_cloud_sharing

Diff for: user_manual/files/using_e2ee.rst

@@ -0,0 +1,149 @@
+=============================================
+Using end-to-end encryption
+=============================================
+
+If enabled server side, Nextcloud provides the possibility to encrypt your files on your devices.
+This is called end-to-end encryption, or E2EE, because the files are encrypted on your device and only decrypted on your device.
+This means that the server never sees the unencrypted files.
+
+Enabling E2EE
+-------------
+
+If your administrator enabled the end-to-end encryption app, you can start using it from one of your devices.
+Open the settings of the Nextcloud client and look for the EE2E encryption settings.
+
+Desktop
+^^^^^^^
+
+.. image:: ../images/e2ee-desktop-setup.png
+    :width: 750px
+    :alt: Setup E2EE on the desktop client
+
+Android
+^^^^^^^
+
+.. image:: ../images/e2ee-android-setup.png
+    :width: 400px
+    :alt: Setup E2EE on Android
+
+iOS
+^^^
+
+.. image:: ../images/e2ee-ios-setup.png
+    :width: 400px
+    :alt: Setup E2EE on iOS
+
+Web
+^^^
+
+.. warning::
+
+    It is not possible to enable E2EE in the browser.
+
+Encrypting a folder
+-----------------------
+
+.. warning::
+
+    You can only encrypt empty folders.
+
+Desktop
+^^^^^^^
+
+.. image:: ../images/e2ee-desktop-encrypt.png
+    :width: 750px
+    :alt: Encrypting a folder on the desktop client
+
+Android
+^^^^^^^
+
+.. image:: ../images/e2ee-android-encrypt.png
+    :width: 400px
+    :alt: Encrypting a folder on an Android device
+
+iOS
+^^^
+
+.. image:: ../images/e2ee-ios-encrypt.png
+    :width: 400px
+    :alt: Encrypting a folder on an iOS device
+
+Web
+^^^
+
+.. warning::
+
+    It is not possible to encrypt a folder in the browser.
+
+Adding an E2EE device
+---------------------
+
+Desktop
+^^^^^^^
+
+.. image:: ../images/e2ee-desktop-add.png
+    :width: 750px
+    :alt: Setup a new desktop client
+
+Android
+^^^^^^^
+
+.. image:: ../images/e2ee-android-add.png
+    :width: 400px
+    :alt: Setup a new Android device
+
+iOS
+^^^
+
+.. image:: ../images/e2ee-ios-add.png
+    :width: 400px
+    :alt: Setup a new iOS device
+
+Web
+^^^
+
+In the browser, you'll first have to enable E2EE in the personal settings. This needed, as E2EE is less secure in the browser as you need to fully trust your administrator to not alter the source code that your browser will execute.
+E2EE folders are currently read-only. Therefore, it is not possible to add, remove, edit, or share an E2EE file from the browser.
+
+.. image:: ../images/e2ee-web-add-1.png
+    :width: 750px
+    :alt: Setup a new browser session step 1
+
+.. image:: ../images/e2ee-web-add-2.png
+    :width: 750px
+    :alt: Setup a new browser session step 2
+
+.. image:: ../images/e2ee-web-add-3.png
+    :width: 750px
+    :alt: Setup a new browser session step 3
+
+Displaying the mnemonic
+-----------------------
+
+Desktop
+^^^^^^^
+
+.. image:: ../images/e2ee-desktop-mnemonic.png
+    :width: 750px
+    :alt: Displaying the mnemonic on the desktop client
+
+Android
+^^^^^^^
+
+.. image:: ../images/e2ee-android-mnemonic.png
+    :width: 400px
+    :alt: Displaying the mnemonic on an Android device
+
+iOS
+^^^
+
+.. image:: ../images/e2ee-ios-mnemonic.png
+    :width: 400px
+    :alt: Displaying the mnemonic on an iOS device
+
+Web
+^^^
+
+.. warning::
+
+    It is not possible to display the mnemonic in the browser.