Encryption Configuration

If you are upgrading from ownCloud 8.0, and have encryption enabled, please see Encryption migration to ownCloud 8.0 (below) for the correct steps to upgrade your encryption.

In ownCloud 8.1 and up the server-side encryption has a number of changes and improvements, including:

  • When encryption is enabled, all files are no longer encrypted at user’s first logins because this causes timeouts on large installations. Instead, only files that are created or updated after encryption has been enabled are encrypted.
  • The “decrypt all” option in the Personal settings has been removed, also for performance reasons.
  • A new option for users to enable/disable encryption on a per mount-point basis.
  • The option to choose from multiple encryption modules.

ownCloud server-side encryption encrypts files stored on the ownCloud server, and files on remote storage that is connected to your ownCloud server. Encryption and decryption are performed on the ownCloud server. All files sent to remote storage (for example Dropbox and Google Drive) will be encrypted by the ownCloud server, and upon retrieval, decrypted before serving them to you and anyone you have shared them with.

Note

Encrypting files increases their size by roughly 35%, so you must take this into account when you are provisioning storage and setting storage quotas. User’s quotas are based on the unencrypted file size, and not the encrypted file size.

When files on external storage are encrypted in ownCloud, you cannot share them directly from the external storage services, but only through ownCloud sharing because the key to decrypt the data never leaves the ownCloud server.

The main purpose of the ownCloud server-side encryption is to protect users’ files on remote storage, and to do it easily and seamlessly from within ownCloud.

ownCloud’s server-side encryption generates a strong encryption key, which is unlocked by user’s passwords. Your users don’t need to track an extra password, but simply log in as they normally do. It encrypts only the contents of files, and not filenames and directory structures.

You should regularly backup all encryption keys to prevent permanent data loss. The encryption keys are stored in the following directories:

data/<user>/files_encryption
Users’ private keys and all other keys necessary to decrypt the users’ files
data/files_encryption
private keys and all other keys necessary to decrypt the files stored on a system wide external storage

When encryption is enabled, all files are encrypted and decrypted by the ownCloud application, and stored encrypted on your remote storage. This protects your data on externally hosted storage. The ownCloud admin and the storage admin will see only encrypted files when browsing backend storage.

Warning

Encryption keys are stored only on the ownCloud server, eliminating exposure of your data to third-party storage providers. The encryption app does not protect your data if your ownCloud server is compromised, and it does not prevent ownCloud administrators from reading user’s files. This would require client-side encryption, which this app does not provide. If your ownCloud server is not connected to any external storage services then it is better to use other encryption tools, such as file-level or whole-disk encryption.

Note also that SSL terminates at or before Apache on the ownCloud server, and all files will exist in an unencrypted state between the SSL connection termination and the ownCloud code that encrypts and decrypts files. This is also potentially exploitable by anyone with administrator access to your server. Read How ownCloud uses encryption to protect your data for more information.

Before Enabling Encryption

Plan very carefully before enabling encryption because it is not reversible, and if you lose your encryption keys your files are not recoverable. Always have backups of your encryption keys stored in a safe location, and consider enabling all recovery options.

Enabling Encryption

ownCloud encryption now consists of two parts. The base encryption system is enabled and disabled on your Admin page. First you must enable this, and then select an encryption module to load. Currently the only available encryption module is the ownCloud Default Encryption Module.

First go to the Server-side encryption section of your Admin page and check Enable server-side encryption. You have one last chance to change your mind.

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After clicking the Enable Encryption button you see the message “No encryption module loaded, please load a encryption module in the app menu”, so go to your Apps page to enable the ownCloud Default Encryption Module.

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Return to your Admin page to see the ownCloud Default Encryption Module added to the module selector, and automatically selected. Now you must log out and then log back in to initialize your encryption keys.

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Sharing Encrypted Files

After encryption is enabled your users must also log out and log back in to generate their personal encryption keys. They will see a yellow warning banner that says “Encryption App is enabled but your keys are not initialized, please log-out and log-in again.”

Share owners may need to re-share files after encryption is enabled; users trying to access the share will see a message advising them to ask the share owner to re-share the file with them. For individual shares, un-share and re-share the file. For group shares, share with any individuals who can’t access the share. This updates the encryption, and then the share owner can remove the individual shares.

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Enabling Users’ File Recovery Key

If you lose your ownCloud password, then you lose access to your encrypted files. If one of your users loses their ownCloud password their files are unrecoverable. You cannot reset their password in the normal way; you’ll see a yellow banner warning “Please provide an admin recovery password, otherwise all user data will be lost”.

To avoid all this, create a Recovery Key. Go to the Encryption section of your Admin page and set a recovery key password.

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Then your users have the option of enabling password recovery on their Personal pages. If they do not do this, then the Recovery Key won’t work for them.

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For users who have enabled password recovery, give them a new password and recover access to their encrypted files by supplying the Recovery Key on the Users page.

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You may change your Recovery Key password.

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occ Encryption Commands

You may also use the occ command to perform encryption operations.

Get the current status of encryption and the loaded encryption module:

occ encryption:status

This is equivalent to checking Enable server-side encryption on your Admin page:

occ encryption:enable

List the available encryption modules:

occ encryption:list-modules

Select a different default Encryption module:

occ encryption:set-default-module [Module ID].

The [module ID] is taken from the encryption:list-modules command.

See Using the occ Command for detailed instructions on using occ.

Files Not Encrypted

Only the data in your files is encrypted, and not the filenames or folder structures. These files are never encrypted:

  • Old files in the trash bin
  • Image thumbnails from the Gallery app
  • Previews from the Files app
  • The search index from the full text search app
  • Third-party app data

There may be other files that are not encrypted; only files that are exposed to third-party storage providers are guaranteed to be encrypted.

LDAP and Other External User Back-ends

If you use an external user back-end, such as an LDAP or Samba server, and you change a user’s password on the back-end, the user will be prompted to change their ownCloud login to match on their next ownCloud login. The user will need both their old and new passwords to do this. If you have enabled the Recovery Key then you can change a user’s password in the ownCloud Users panel to match their back-end password, and then, of course, notify the user and give them their new password.

Encryption migration to ownCloud 8.0

When you upgrade from older versions of ownCloud to ownCloud 8.0, you must manually migrate your encryption keys with the occ command after the upgrade is complete, like this example for CentOS: sudo -u apache php occ encryption:migrate-keys You must run occ as your HTTP user. See Using the occ Command to learn more about occ.

Encryption migration to ownCloud 8.1

The encryption backend has changed in ownCloud 8.1 again, so you must take some additional steps to migrate encryption correctly. If you do not follow these steps you may not be able to access your files.

Before you start your upgrade, put your ownCloud server into maintenance:singleuser mode (See Maintenance Mode Configuration.) You must do this to prevent users and sync clients from accessing files before you have completed your encryption migration.

After your upgrade is complete, follow the steps in Enabling Encryption to enable the new encryption system. Then click the Start Migration button on your Admin page to migrate your encryption keys, or use the occ command. We strongly recommend using the occ command; the Start Migration button is for admins who do not have access to the console, for example installations on shared hosting. This example is for Debian/Ubuntu Linux:

$ sudo -u www-data php occ encryption:migrate

This example is for Red Hat/CentOS/Fedora Linux:

$ sudo -u apache php occ encryption:migrate

You must run occ as your HTTP user; see Using the occ Command.

When you are finished, take your ownCloud server out of maintenance:singleuser mode.

Where Keys are Stored

All of your encryption keys are stored in your ownCloud data/ directory. When you run the migration command your old keys are backed up in your data directory:

Backup for system-wide keys:
data/encryption_migration_backup_<timestamp>
Backup for user-specific keys:
data/<user>/encryption_migration_backup_<timestamp>

Both backup directories contain the keys in the old file structure. This is the old file structure for ownCloud 8.0:

Private public share key:
data/files_encryption/pubShare_<public-share-key-id>.privateKey
Private recovery key:
data/files_encryption/recovery_<recovery-key-id>.privateKey
Public keys of all users:
data/files_encryption/public_keys
File keys for system-wide mount points:
data/files_encryption/keys/<file_path>/<filename>/fileKey
Share keys for files on a system-wide mount point (one key for the owner and one key for each user with access to the file):
data/files_encryption/keys/<file_path>/<filename>/<user>.shareKey
Users’ private keys:
data/<user>/files_encryption/<user>.privateKey
File keys for files owned by the user:
data/<user>/files_encryption/keys/<file_path>/<filename>/fileKey
Share keys for files owned by the user (one key for the owner and one key for each user with access to the file):
data/<user>/files_encryption/keys/<file_path>/<filename>/<user>.shareKey

This is the new file structure for ownCloud 8.1:

Private public share key:
data/files_encryption/OC_DEFAULT_MODULE/pubShare_<public-share-key-id>.privateKey
Private recovery key:
data/files_encryption/OC_DEFAULT_MODULE/recovery_<recovery-key-id>.privateKey
Public public share key:
data/files_encryption/OC_DEFAULT_MODULE/pubShare_<public-share-key-id>.publicKey
Public recovery key:
data/files_encryption/OC_DEFAULT_MODULE/recovery_<recovery-key-id>.publicKey
File keys for system-wide mount points:
data/files_encryption/keys/<file_path>/<filename>/OC_DEFAULT_MODULE/fileKey
Share keys for files on a system-wide mount point (one key for the owner and one key for each user with access to the file):
data/files_encryption/keys/<file_path>/<filename>/OC_DEFAULT_MODULE/<user>.shareKey
Users’ private keys:
data/<user>/files_encryption/OC_DEFAULT_MODULE/<user>.privateKey
Users’ public keys:
data/<user>/files_encryption/OC_DEFAULT_MODULE/<user>.publicKey
File keys for files owned by the user:
data/<user>/files_encryption/keys/<file_path>/<filename>/OC_DEFAULT_MODULE/fileKey
Share keys for files owned by the user (one key for the owner and one key for each user with access to the file):
data/<user>/files_encryption/keys/<file_path>/<filename>/OC_DEFAULT_MODULE/<user>.shareKey
All documentation licensed under the Creative Commons Attribution 3.0 Unported license.