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Encryption Key Management

On this page

  • Encryption Components
  • Supported Key Management Services
  • Manage a Data Encryption Key's Alternate Name
  • Create a Data Encryption Key with an Alternate Name
  • Use Key Alternate Names in an Automatic Encryption Schema
  • Procedure: Rotate Encryption Keys Using Mongo Shell
  • Delete a Data Encryption Key
  • Learn More

In this guide, you can learn how to manage your encryption keys with a Key Management System (KMS) in your Client-Side Field Level Encryption (CSFLE)-enabled application.

MongoDB uses the following components to perform Client-Side Field Level Encryption:

  • Data Encryption Keys (DEK)s

  • Customer Master Keys (CMK)s

  • Key Vault collections

  • Key Management System (KMS)

To learn more about keys and key vaults, see Encryption Keys and Key Vaults.

Client-Side Field Level Encryption supports the following Key Management System providers:

  • Amazon Web Services KMS

  • Azure Key Vault

  • Google Cloud KMS

  • Any KMIP Compliant Key Management System

  • Local Key Provider (for testing only)

The default KMIP protocol version is 1.2. You can configure MongoDB to use KMIP version 1.0 or 1.1 in the MongoDB server configuration file.

To learn more about these providers, including diagrams that show how your application uses them to perform Client-Side Field Level Encryption, see KMS Providers.

You can assign a Data Encryption Key alternate names to make the key easier to reference. Assigning alternate names allows you to perform the following actions:

  • Reference a DEK by different means than the _id field.

  • Dynamically assign DEKs at runtime.



Prior to adding a new key alternate name, you must create a partial unique index on the keyAltNames field. This index should have a partialFilterExpression for documents where keyAltNames exists.

Client-Side Field Level Encryption depends on server-enforced uniqueness of key alternate names.

To learn how to create a partial index, refer to Partial Indexes.

The following example creates a Data Encryption Key with an alternate name. Select the tab that corresponds to your driver language:

var autoEncryptionOpts = {
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders,
var encryptedClient = Mongo(
var clientEncryption = encryptedClient.getClientEncryption();
var masterKey = {
"<Your dataKeyOpts Key>": "<Your dataKeyOpts Value>",
var keyVault = encryptedClient.getKeyVault();
var keyId = keyVault.createKey("aws", masterKey, ["<Your Key Alt Name>"]);
var keyVaultClient = new MongoClient(connectionString);
var clientEncryptionOptions = new ClientEncryptionOptions(
keyVaultClient: keyVaultClient,
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders);
var clientEncryption = new ClientEncryption(clientEncryptionOptions);
var dataKeyOptions = new DataKeyOptions(
alternateKeyNames: new[] { "<Your Key Alt Name>" },
masterKey: new BsonDocument
{ "<Your dataKeyOpts Keys>", "<Your dataKeyOpts Values>" },
var dataKeyId = clientEncryption.CreateDataKey("<Your KMS Provider>", dataKeyOptions, CancellationToken.None);
clientEncryptionOpts := options.ClientEncryption().SetKeyVaultNamespace(KeyVaultNamespace).SetKmsProviders(kmsProviders)
keyVaultClient, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(URI))
if err != nil {
return fmt.Errorf("Client connect error %v", err)
clientEnc, err := mongo.NewClientEncryption(keyVaultClient, clientEncryptionOpts)
if err != nil {
return fmt.Errorf("NewClientEncryption error %v", err)
defer func() {
_ = clientEnc.Close(context.TODO())
masterKey := map[string]interface{}{
"<Your dataKeyOpts Key>": "<Your dataKeyOpts Value>",
dataKeyOpts := options.DataKey().
SetKeyAltNames([]string{"<Your Key Alt Name>"})
dataKeyID, err := clientEnc.CreateDataKey(context.TODO(), provider, dataKeyOpts)
if err != nil {
return fmt.Errorf("create data key error %v", err)
ClientEncryptionSettings clientEncryptionSettings = ClientEncryptionSettings.builder()
.applyConnectionString(new ConnectionString(connectionString))
ClientEncryption clientEncryption = ClientEncryptions.create(clientEncryptionSettings);
BsonDocument masterKeyProperties = new BsonDocument();
masterKeyProperties.put("provider", new BsonString("<Your KMS Provider>"));
masterKeyProperties.put("<Your dataKeyOpts Key>", new BsonString("<Your dataKeyOpts Value>"));
List keyAltNames = new ArrayList<String>();
keyAltNames.add("<Your Key Alt Name>");
BsonBinary dataKeyId = clientEncryption.createDataKey(kmsProvider, new DataKeyOptions().masterKey(masterKeyProperties).keyAltNames(keyAltNames));
const encryption = new ClientEncryption(client, {
const masterKey = {
"<Your dataKeyOpts Key>": "<Your dataKeyOpts Value>",
const key = await encryption.createDataKey(provider, {
masterKey: masterKey,
keyAltNames: ["<Your Key Alt Name>"],
client = MongoClient(connection_string)
client_encryption = ClientEncryption(
master_key={ "<Your dataKeyOpts Key>" : "<Your dataKeyOpts Value>"}
data_key_id = client_encryption.create_data_key(provider, master_key, key_alt_names=["<Your Key Alt Name>"])

To learn more about dataKeyOpts and kmsProviders objects, see KMS Providers.

Encryption schemas contain user-specified rules that identify which fields must be encrypted and how to encrypt those fields. In your encryption rules, you can specify alternate key names name for the Data Encryption Key which encrypts your field.

You must refer to a key alternate name with a JSON pointer. A JSON pointer is a string prefixed with a "/" character that can be used to access a particular field value in the same or another document. Use JSON pointers to reference a field in your query or update document which contains the value of your key alternate name.


Cannot Use Alternate Name for Deterministically Encrypted Field

You cannot reference a DEK by it's alternate name when encrypting a field with the deterministic encryption algorithm. To encrypt your field deterministically, you must specify the _id of the key you would like to use to encrypt your field.

Consider the following encryption schema which encrypts the salary field:

"<database>.<collection>": {
"bsonType": "object",
"properties": {
"salary": {
"encrypt": {
"bsonType": "int",
"keyId": "/fieldWithAltName",
"algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"

The schema's keyId field contains a JSON pointer to reference the fieldWithAltName field within the documents being encrypted.

The following document's fieldWithAltName value is my-alt-name:

"name": "Jon Doe",
"salary": 45000,
"fieldWithAltName": "my-alt-name"

The salary field is encrypted by the DEK that has the alternate name my-alt-name.

You can use alternate key names to dynamically set the Data Encryption Key for a field at runtime. Use this functionality to encrypt individual documents with different DEKs using the same encryption schema.

For example, consider the following documents:

"name": "Jon Doe",
"salary": 45000,
"fieldWithAltName": "my-alt-name"
"name": "Jane Smith",
"salary": 70000,
"fieldWithAltName": "my-other-alt-name"

You insert the preceding documents using a CSFLE-enabled client configured with the encryption schema from the previous example.

In the encryption schema, the salary.encrypt.keyId field contains a JSON pointer to the fieldWithAltName field of the inserted document. As a result, the salary fields in the two example documents are each encrypted using a DEK specific to the individual document. The keys are assigned dynamically at runtime.

With version 1.5 and later of the Mongo Shell, you can rotate encryption keys using the rewrapManyDataKey method. The rewrapManyDataKey method automatically decrypts multiple data keys and re-encrypts them using a specified Customer Master Key. It then updates the rotated keys in the key vault collection. This method allows you to rotate encryption keys based on two optional arguments:

  • A filter used to specify which keys to rotate. If no data key matches the given filter, no keys are rotated. Omit the filter to rotate all keys in your key vault collection.

  • An object that represents a new CMK. Omit this object to rotate the data keys using their current CMKs.

The rewrapManyDataKey uses the following syntax:

keyVault = db.getKeyVault()
"<Your custom filter>"
provider: "<KMS provider>",
masterKey: {
"<dataKeyOpts Key>" : "<dataKeyOpts Value>"

To learn more about the dataKeyOpts object for your KMS provider, see Supported Key Management Services.

You can delete a Data Encryption Key from your Key Vault collection using standard CRUD delete operations. If you delete a DEK, all fields encrypted with that DEK become permanently unreadable.


MongoDB Shell Specific Feature

The MongoDB shell allows you to delete a DEK by UUID using the keyVault.deleteKey() method as follows:

keyVault = db.getKeyVault()
keyVault.deleteKey(UUID("<UUID String>"))

To learn more about Key Vault collections see Encryption Keys and Key Vaults.

For tutorials detailing how to set up a CSFLE-enabled application with each of the supported KMS providers, see the following pages:

To view additional examples of encryption schemas, see CSFLE Encryption Schemas.


Encryption Schemas


Fields and Encryption Types