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New in version 4.2.


Client-Side Field Level Encryption is available as a beta. The contents of this page may change during the beta period.


Returns the KeyVault object for the current database connection. The KeyVault object supports data key management for Client-side field level encryption.

getKeyVault() has the following syntax:

keyVault = db.getMongo().getKeyVault();
returns:The KeyVault object for current database connection.

Use the KeyVault object to access the following data key management methods:


Requires Configuring Client-Side Field Level Encryption on Database Connection

The mongo client-side field level encrytion methods require a database connection with client-side field level encryption enabled. If the current database connection was not initiated with client-side field level encryption enabled, either:

  • Use the Mongo() constructor from the mongo shell to establish a connection with the required client-side field level encryption options. The Mongo() method supports both Amazon Web Services and Local Key Management Service (KMS) providers for Customer Master Key (CMK) management.


  • Use the mongo shell command line options to establish a connection with the required options. The command line options only support the AWS KMS provider for CMK management.

Unique Partial Index on Key Vault

The getKeyVault() method automatically creates a unique index on keyAltNames` with a partial index filter for only documents where keyAltNames exists. This prevents any two data keys from having the same key alternative name and therefore avoids ambiguity around which data key is appropriate for encryption/decryption.


Do not drop the unique index created by getKeyVault(). Client-side field level encryption operations depend on server-enforced uniqueness of keyAltNames. Removing the index may lead to unexpected or unpredictable behavior.



To mitigate the risk of the AWS Access Key or AWS Secret Key leaking into logs, consider specifying an environment variable containing the required values as part of the mongo startup. For example, the following operation loads the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables into local variables in the mongo shell:

mongo --eval "
  " \

Use the created AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY variables in the shell to reference the AWS credentials.

The following operation issued from the mongo shell:

  • Establishes a connection to the cluster with client-side field level encryption enabled.
  • Retrieves the key vault object using the encryption-enabled connection object.
ClientSideOptions = {
  "keyVaultNamespace" : "encryption.dataKeys",
  "kmsProviders" : {
    "aws" : {
      "accessKeyId" : "AWS_ACCESS_KEY_ID",
      "secretAccessKey" : "AWS_SECRET_ACCESS_KEY"

encryptedClient = Mongo(

keyVault = encryptedClient.getKeyVault();

For complete documentation on initiating MongoDB connections with client-side field level encryption enabled, see Mongo().