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  • Behavior
  • Example
KeyVault.createKey(keyManagementService, customerMasterKey, ["keyAltName"])

Adds a data encryption key to the key vault associated to the database connection. Client-Side Field Level Encryption uses data encryption keys for supporting encryption and decryption of field values.

createKey() has the following syntax:

keyVault = db.getMongo().getKeyVault()
[ "keyAltName" ]


The Key Management Service (KMS) to use for retrieving the Customer Master Key (CMK). Accepts the following parameters:

  • aws for Amazon Web Services KMS. Requires specifying a Customer Master Key (CMK) string for customerMasterKey.

  • azure for Azure Key Vault. Requires specifying a Customer Master Key (CMK) document for customerMasterKey.

    New in version 5.0.

  • gcp for Google Cloud Platform KMS. Requires specifying a Customer Master Key (CMK) document for customerMasterKey.

    New in version 5.0.

  • local for a locally managed key.

If the database connection was not configured with the specified KMS, data encryption key creation fails.

string or document

The Customer Master Key (CMK) to use for encrypting the data encryption key. Required if keyManagementService is aws, azure, or gcp.

Provide the CMK as follows depending on your KMS provider:

createKey() requests that the KMS encrypt the data encryption key material using the specified CMK. If the CMK does not exist or if the AutoEncryptionOpts configuration does not have sufficient privileges to use the CMK, createKey() returns an error.

This parameter has no effect if keyManagementService is local and can be safely omitted.

array of strings


The alternative name for the data encryption key. Use keyAltName to improve findability of a specific data encryption key, or as an analog to a comment.

The getKeyVault() method automatically creates a unique index on the keyAltNames field with a partial index filter for only documents where keyAltNames exists.



A document that specifies options for the new key. options has the following fields:

  • masterKey: the new master key to encrypt data.

  • keyAltNames: an array of alternate names, one per master key.

  • keyMaterial: bindata used to create the key.

Returns:The UUID unique identifier of the created data encryption key.

The mongosh client-side field level encryption 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:

The following example is intended for rapid evaluation of client-side field level encryption. For specific examples of using KeyVault.createKey() with each supported KMS provider, see Create a Data Key.


Start the mongosh client.

mongosh --nodb

To configure client-side field level encryption for a locally managed key, generate a base64-encoded 96-byte string with no line breaks.

const TEST_LOCAL_KEY = require("crypto").randomBytes(96).toString("base64")

Create the client-side field level encryption options using the generated local key string:

var autoEncryptionOpts = {
"keyVaultNamespace" : "encryption.__dataKeys",
"kmsProviders" : {
"local" : {
"key" : BinData(0, TEST_LOCAL_KEY)

Use the Mongo() constructor with the client-side field level encryption options configured to create a database connection. Replace the mongodb:// URI with the connection string URI of the target cluster.

encryptedClient = Mongo(

Retrieve the keyVault object and use the KeyVault.createKey() method to create a new data encryption key using the locally managed key:

keyVault = encryptedClient.getKeyVault()
keyVault.createKey("local", ["data-encryption-key"])

If successful, createKey() returns the UUID of the new data encryption key. To retrieve the new data encryption key document from the key vault, either:





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