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Client Side Encryption

New in MongoDB 4.2 client side encryption allows administrators and developers to encrypt specific data fields in addition to other MongoDB encryption features.

With field level encryption, developers can encrypt fields client side without any server-side configuration or directives. Client-side field level encryption supports workloads where applications must guarantee that unauthorized parties, including server administrators, cannot read the encrypted data.


Support for client side encryption is in beta. Backwards-breaking changes may be made before the final release.


The recommended way to get started using field level encryption in your project is with a dependency management system. Field level encryption requires additional packages to be installed as well as the driver itself.
See the installation for instructions on how to install the MongoDB driver.


There is a separate jar file containinglibmongocrypt bindings.


Note: You can also download the mongodb-crypt jar directly from sonatype.

mongocryptd configuration

libmongocrypt requires the mongocryptd daemon / process to be running. A specific daemon / process uri can be configured in the AutoEncryptionSettings class by setting mongocryptdURI in the extraOptions.

More information about mongocryptd will soon be available from the official documentation.


The following is a sample app that assumes the key and schema have already been created in MongoDB. The example uses a local key, however using AWS Key Management Service is also an option. The data in the encryptedField field is automatically encrypted on the insert and decrypted when using find on the client side. The following code snippet comes from the example code that can be found with the driver source on github:

import com.mongodb.AutoEncryptionSettings;
import com.mongodb.MongoClientSettings;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import org.bson.Document;

import java.util.HashMap;
import java.util.Map;

public class ClientSideEncryptionSimpleTour {

    public static void main(final String[] args) {

        // This would have to be the same master key as was used to create the encryption key
        final byte[] localMasterKey = new byte[96];
        new SecureRandom().nextBytes(localMasterKey);

        Map<String, Map<String, Object>> kmsProviders = new HashMap<String, Map<String, Object>>() {{
           put("local", new HashMap<String, Object>() {{
               put("key", localMasterKey);

        String keyVaultNamespace = "admin.datakeys";

        AutoEncryptionSettings autoEncryptionSettings = AutoEncryptionSettings.builder()

        MongoClientSettings clientSettings = MongoClientSettings.builder()

        MongoClient mongoClient = MongoClients.create(clientSettings);
        MongoCollection<Document> collection = mongoClient.getDatabase("test").getCollection("coll");
        collection.drop(); // Clear old data

        collection.insertOne(new Document("encryptedField", "123456789"));


Auto encryption is an enterprise only feature.

The following example shows how to configure the AutoEncryptionSettings instance to create a new key and setting the json schema map. The full code snippet can be found in

import com.mongodb.ClientEncryptionSettings;
import com.mongodb.ConnectionString;
import com.mongodb.client.model.vault.DataKeyOptions;
import com.mongodb.client.vault.ClientEncryption;
import com.mongodb.client.vault.ClientEncryptions;
import org.bson.BsonBinary;
import org.bson.BsonDocument;

import java.util.Base64;


String keyVaultNamespace = "admin.datakeys";
ClientEncryptionSettings clientEncryptionSettings = ClientEncryptionSettings.builder()
                .applyConnectionString(new ConnectionString("mongodb://localhost"))

ClientEncryption clientEncryption = ClientEncryptions.create(clientEncryptionSettings);
BsonBinary dataKeyId = clientEncryption.createDataKey("local", new DataKeyOptions());
final String base64DataKeyId = Base64.getEncoder().encodeToString(dataKeyId.getData());

final String dbName = "test";
final String collName = "coll";
AutoEncryptionSettings autoEncryptionSettings = AutoEncryptionSettings.builder()
        .schemaMap(new HashMap<String, BsonDocument>() {{
            put(dbName + "." + collName,
                    // Need a schema that references the new data key
                            + "  properties: {"
                            + "    encryptedField: {"
                            + "      encrypt: {"
                            + "        keyId: [{"
                            + "          \"$binary\": {"
                            + "            \"base64\": \"" + base64DataKeyId + "\","
                            + "            \"subType\": \"04\""
                            + "          }"
                            + "        }],"
                            + "        bsonType: \"string\","
                            + "        algorithm: \"AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic\""
                            + "      }"
                            + "    }"
                            + "  },"
                            + "  \"bsonType\": \"object\""
                            + "}"));

Coming soon: An example using the community version and demonstrating explicit encryption/decryption.