Encryption at Rest¶
Encryption at rest, when used in conjunction with transport encryption and good security policies that protect relevant accounts, passwords, and encryption keys, can help ensure compliance with security and privacy standards, including HIPAA, PCI-DSS, and FERPA.
Encrypted Storage Engine¶
New in version 3.2.
Available in MongoDB Enterprise only.
MongoDB Enterprise 3.2 introduces a native encryption option for the WiredTiger storage engine. This feature allows MongoDB to encrypt data files such that only parties with the decryption key can decode and read the data.
MongoDB Enterprise on Windows no longer supports
cipher is now available only on Linux.
If encryption is enabled, the default encryption mode that MongoDB
Enterprise uses is the
AES256-CBC (or 256-bit Advanced Encryption
Standard in Cipher Block Chaining mode) via OpenSSL. AES-256 uses a
symmetric key; i.e. the same key to encrypt and decrypt text. MongoDB
Enterprise for Linux also supports authenticated encryption
AES256-GCM (or 256-bit Advanced Encryption Standard in
Galois/Counter Mode). FIPS mode encryption is also available.
For encrypted storage engines that
AES256-GCM encryption mode,
AES256-GCM requires that every
process use a unique counter block value with the key.
For encrypted storage engine
- Restoring from Hot Backup
- Starting in 4.2, if you restore from files taken via "hot"
backup (i.e. the
mongodis running), MongoDB can detect "dirty" keys on startup and automatically rollover the database key to avoid IV (Initialization Vector) reuse.
- Restoring from Cold Backup
However, if you restore from files taken via "cold" backup (i.e. the
mongodis not running), MongoDB cannot detect "dirty" keys on startup, and reuse of IV voids confidentiality and integrity guarantees.
Starting in 4.2, to avoid the reuse of the keys after restoring from a cold filesystem snapshot, MongoDB adds a new command-line option
--eseDatabaseKeyRollover. When started with the
mongodinstance rolls over the database keys configured with
AES256-GCMcipher and exits.
- In general, if using filesystem based backups for MongoDB Enterprise 4.2+, use the "hot" backup feature, if possible.
- For MongoDB Enterprise versions 4.0 and earlier, if you use
AES256-GCMencryption mode, do not make copies of your data files or restore from filesystem snapshots ("hot" or "cold").
The data encryption process includes:
- Generating a master key.
- Generating keys for each database.
- Encrypting data with the database keys.
- Encrypting the database keys with the master key.
The encryption occurs transparently in the storage layer; i.e. all data files are fully encrypted from a filesystem perspective, and data only exists in an unencrypted state in memory and during transmission.
The database keys are internal to the server and are only paged to disk in an encrypted format. MongoDB never pages the master key to disk under any circumstances.
Only the master key is external to the server (i.e. kept separate from the data and the database keys), and requires external management. To manage the master key, MongoDB's encrypted storage engine supports two key management options:
- Integration with a third party key management appliance via the Key Management Interoperability Protocol (KMIP). Recommended
- Local key management via a keyfile.
To configure MongoDB for encryption and use one of the two key management options, see Configure Encryption.
Encryption and Replication¶
Encryption is not a part of replication:
- Master keys and database keys are not replicated, and
- Data is not natively encrypted over the wire.
Although you could reuse the same key for the nodes, MongoDB recommends the use of individual keys for each node as well as the use of transport encryption.
For details, see Rotate Encryption Keys.
New in version 3.4: Available in MongoDB Enterprise only
The log file is not encrypted as a part of MongoDB's encrypted storage engine.
mongod running with logging
may output potentially sensitive information to log files as a part of normal
operations, depending on the configured log verbosity.
MongoDB 3.4 Enterprise provides the
setting to prevent potentially sensitive information from entering the
mongod process log.
reduces detail in the log and may complicate log diagnostics.
See the log redaction manual entry for more information.
Application Level Encryption¶
Application Level Encryption provides encryption on a per-field or per-document basis within the application layer.
New in version 4.2: MongoDB 4.2-series drivers provides a client-side field level encryption framework. For more information, see Client-Side Field Level Encryption.
To encrypt full documents, write custom encryption and decryption routines or use a commercial solution.
For a list of MongoDB's certified partners, refer to the Partners List.