added the encryption details page which decribes the server-side encr…

[yahesh]

…yption implementation of the default encryption module

As was advised in the nextcloud/server issue #16419 we provide the description of the server-side encryption as a ReStructuredText document. As this document will likely have another target audience than the existing "Encryption configuration" page we created a separate "Encryption details" page.

[jknockaert]

I had a look at the text. It's definitely a good idea to document this topic, so thank you for your effort. My knowledge about the encryption mechanism in nextcloud is limited to the encryption wrapper, and as far as that mechanism is concerned the text seems correct, with just one omission that you may want to adress.
Very early versions of owncloud had a different encryption scheme. If I remember correctly there was no header in the first block of the encrypted file. The header only came upon the first revision of the encryption format. All later versions of owncloud/nextcloud still support that initial (and all later) versions of the encryption format, as encrypted files never get updated when a new version of the format is introduced. After that revision there have been later updates to the encryption format, but I don't remember exactly what they were about. There has been a vulnerability adressed, and also file versioning required some tweaking in the encryption mechanism, but I cannot recall the fine details.
Perhaps you should just mention in your document that you are discussing a specific version of the encrypted file format, and that older versions are still around and supported by nextcloud.

[yahesh]

@jknockaert Thanks for the feedback. I added a note to the introduction that describes that previous versions of Nextcloud implemented slightly different encryption schemes and that these files may till be around.

[yahesh]

@rullzer @MorrisJobke @schiessle @jknockaert Hi, this PR is now stalled for a over a month. Is there something we can help with to get this PR approved?

[J0WI]

cc @nextcloud/encryption

[J0WI]

Maybe you could also add a reference to E2E to fix #1275.

[J0WI]

Oh and maybe a note that app data (calendar, contacts, chats etc.) are stored in the database and not encrypted.

[yahesh]

Maybe you could also add a reference to E2E to fix #1275.

The server-side encryption is a totally different concept compared to the client-side E2E encryption. So "referencing" it just to fix that issue doesn't seem like a viable solution.

[yahesh]

Oh and maybe a note that app data (calendar, contacts, chats etc.) are stored in the database and not encrypted.

IMHO the document already goes into great detail what gets encrypted by the server-side encryption. From the details it should become obvious that data within the database do not get encrypted. :)

[yahesh]

@rullzer @MorrisJobke @schiessle @jknockaert Another month has gone by.

[yahesh]

@rullzer @MorrisJobke @schiessle @jknockaert Hi there, another month has passed. Did you find the time to review this pull request? 🙂

[skjnldsv]

@yahesh unfortunately Morris is unavailable and everyone is completely booked!

Maybe @J0WI and @jknockaert can help and review? :)

[J0WI]

The recovery key is only used if user keys are activated and no master key is used. Both, the admin and the user must enable the recovery key:
https://docs.nextcloud.com/server/stable/admin_manual/configuration_files/encryption_configuration.html#enabling-users-file-recovery-keys

[J0WI]

Suggested change

While the user key encryption has been enabled by default in older versions of Nextcloud it now has to be enabled explictly in newer versions including Nextcloud 16 by calling ``./occ encryption:disable-master-key``. With user key encryption enabled all users have their own user keys that are used to secure the files handled by Nextcloud. The user keys are protected by the user passwords. The advantage is that the server administrator is not able to decrypt user files without knowing any user password - unless the file is publicly shared or a recovery key is defined - but has the disadvantage that files are permanently lost if the users forget their user passwords - unless the files are (publicly) shared or a recovery key is defined.

While the user key encryption has been enabled by default in older versions of Nextcloud it now has to be enabled explicitly in newer versions including Nextcloud 16 by calling ``./occ encryption:disable-master-key``. With user key encryption enabled all users have their own user keys that are used to secure the files handled by Nextcloud. The user keys are protected by the user passwords. The advantage is that the server administrator is not able to decrypt user files without knowing any user password - unless the file is publicly shared or a recovery key is defined - but has the disadvantage that files are permanently lost if the users forget their user passwords - unless the files are (publicly) shared or a recovery key is defined.

(explictly => explicitly)

[yahesh]

@J0WI I introduced your recommended changes. :)

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/documentation/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22
Most developers hang out on IRC. So join #nextcloud-dev on Freenode for a chat!

[kesselb]

Thanks @yahesh 👍

[J0WI]

/backport to stable17

[J0WI]

/backport to stable16

[backportbot-nextcloud]

backport to stable17 in #1718

[backportbot-nextcloud]

backport to stable16 in #1719