Encryption at Rest

This feature is only available in the Enterprise Edition

When you store sensitive data in your ArangoDB database, you want to protect that data under all circumstances. At runtime you will protect it with SSL transport encryption and strong authentication, but when the data is already on disk, you also need protection. That is where the Encryption feature comes in.

The Encryption feature of ArangoDB will encrypt all data that ArangoDB is storing in your database before it is written to disk.

The data is encrypted with AES-256-CTR, which is a strong encryption algorithm, that is very suitable for multi-processor environments. This means that your data is safe, but your database is still fast, even under load.

Most modern CPU's have builtin support for hardware AES encryption, which makes it even faster.

The encryption feature is supported by all ArangoDB deployment modes.

Limitations

The encryption feature has the following limitations:

  • Encrypting a single collection is not supported: all the databases are encrypted.
  • It is not possible to enable encryption at runtime: if you have existing data you will need to take a backup first, then enable encryption and start your server on an empty data-directory, and finally restore your backup.
  • The Encryption feature requires the RocksDB storage engine.

Encryption keys

The encryption feature of ArangoDB requires a single 32-byte key per server. It is recommended to use a different key for each server (when operating in a cluster configuration). Make sure to protect these keys!

That means:

  • Do not write them to persistent disks or your server(s), always store them on an in-memory (tmpfs) filesystem.
  • Transport your keys safely to your server(s). There are various tools for managing secrets like this (e.g. vaultproject.io).
  • Store a copy of your key offline in a safe place. If you lose your key, there is NO way to get your data back.

Configuration

To activate encryption of your database, you need to supply an encryption key to the server.

Make sure to pass this option the very first time you start your database. You cannot encrypt a database that already exists.

Note: You also have to activate the RocksDB storage engine.

Encryption key stored in file

Pass the following option to arangod:

$ arangod \
    --rocksdb.encryption-keyfile=/mytmpfs/mySecretKey \
    --server.storage-engine=rocksdb

The file /mytmpfs/mySecretKey must contain the encryption key. This file must be secured, so that only arangod can access it. You should also ensure that in case some-one steals the hardware, he will not be able to read the file. For example, by encryption /mytmpfs or creating a in-memory file-system under /mytmpfs.

Encryption key generated by a program

Pass the following option to arangod:

$ arangod \
    --rocksdb.encryption-key-generator=path-to-my-generator \
    --server.storage-engine=rocksdb

The program path-to-my-generator output the encryption on standard output and exit.

Creating keys

The encryption keyfile must contain 32 bytes of random data.

You can create it with a command line this.

dd if=/dev/random bs=1 count=32 of=yourSecretKeyFile

For security, it is best to create these keys offline (away from your database servers) and directly store them in you secret management tool.