[SOLVED] Decrypting encrypted files (using the default Server-side encryption)

LjKdp3AW · March 11, 2024, 6:47pm

Hello there.

To put it brief I tried to save my volumes from an existing Nextcloud installation during a reinstall but overwrote them. Now I have all my data in a backup, but that is encrypted using the default server-side encryption.

I think I should have all the necessary components to decrypt my data, but I don’t know how. Is there a tool that I can use?

(example file)

Is there any hope or is my backup useless?

I am using this as a wake up call to do best practices, documentation and test restoring backups after creating them.

wwe · March 11, 2024, 8:11pm

if you have data and config files this should help:

github.com

syseleven/nextcloud-tools/blob/master/documentation/server-side-encryption.md

# Nextcloud Server-Side Encryption

This document - provided by [SysEleven](https://syseleven.de) - describes the server-side encryption scheme implemented by Nextcloud's default encryption module. This includes:

* the encryption and signature of files with a master key.
* the encryption and signature of files with a public sharing key.
* the encryption and signature of files with a recovery key.
* the encryption and signature of files with a user key.

These conventions apply throughout this document:

* Given file paths in this document are relative to the Nextcloud data directory that can be retrieved as `datadirectory` from the Nextcloud configuration file (`"config/config.php"`).
* Placeholders are denoted as `$variable`. The variable has to be replaced with the appropriate information.
* Static strings are denoted as `"some string"`.
* The concatenation of strings is denoted as `$variable."some string"`.

## Key Types

### Master Key

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LjKdp3AW · March 11, 2024, 11:15pm

Thanks a lot! This actually works really well once I figured out how to get the script running.

You saved me a lot of despair.

system · March 19, 2024, 11:16pm

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