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Client-Side Encryption

On this page

  • Installation
  • libmongocrypt
  • mongocryptd Configuration
  • Examples
  • Explicit Encryption and Decryption
  • Explicit Encryption and Auto Decryption

Starting in v4.2, MongoDB supports client-side encryption. Client-side encryption allows administrators and developers to encrypt specific data fields in addition to providing other MongoDB encryption features.

With field-level encryption, developers can encrypt fields on the 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.

Important

This guide uses the Subscriber implementations, which are described in the Quick Start Primer.

Installation

The recommended way to get started using field-level encryption in your project is by using a dependency management system. Field-level encryption requires additional packages in addition to the driver.

Note

For instructions about how to install the Java Reactive Streams driver, see the installation guide.

libmongocrypt

There is a separate JAR file containing libmongocrypt bindings.

If you are using Maven to manage your packages, add the following entry to your pom.xml dependencies list:

<dependencies>
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongodb-crypt</artifactId>
        <version>1.2.1</version>
    </dependency>
</dependencies>

If you are using Gradle to manage your packages, add the following entry to your dependencies list:

dependencies {
    implementation 'org.mongodb:mongodb-crypt:1.2.1'
}

mongocryptd Configuration

The libmongocrypt bindings require 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 setting.

Examples

The following example is a sample app that assumes the key and schema have already been created in MongoDB. The example uses a local key, but you can also use the AWS/Azure/GCP Key Management Service. The data in the encryptedField field is automatically encrypted on the insert and decrypted when using find on the client side.

The code example is from the ClientSideEncryptionSimpleTour.java file in the driver source code GitHub repository.

import com.mongodb.AutoEncryptionSettings;
import com.mongodb.MongoClientSettings;
import com.mongodb.reactivestreams.client.MongoClient;
import com.mongodb.reactivestreams.client.MongoClients;
import com.mongodb.reactivestreams.client.MongoCollection;
import org.bson.Document;
import java.security.SecureRandom;
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()
                .keyVaultNamespace(keyVaultNamespace)
                .kmsProviders(kmsProviders)
                .build();
        MongoClientSettings clientSettings = MongoClientSettings.builder()
                .autoEncryptionSettings(autoEncryptionSettings)
                .build();
        MongoClient mongoClient = MongoClients.create(clientSettings);
        MongoCollection<Document> collection = mongoClient.getDatabase("test").getCollection("coll");
        ObservableSubscriber<Void> successSubscriber = new OperationSubscriber<>();
        collection.drop().subscribe(successSubscriber);
        successSubscriber.await();
        successSubscriber = new OperationSubscriber<>();
        collection.insertOne(new Document("encryptedField", "123456789")).subscribe(successSubscriber);
        successSubscriber.await();
        ObservableSubscriber<Document> documentSubscriber = new PrintDocumentSubscriber();
        collection.find().first().subscribe(documentSubscriber);
        documentSubscriber.await();
    }
}

Note

Automatic encryption is an enterprise only feature.

The following example shows how to configure the AutoEncryptionSettings instance to create a new key and set the JSON schema map.

The code example is from the ClientSideEncryptionAutoEncryptionSettingsTour.java file in the driver source code GitHub repository.

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()
    .keyVaultMongoClientSettings(MongoClientSettings.builder()
        .applyConnectionString(new ConnectionString("mongodb://localhost"))
        .build())
    .keyVaultNamespace(keyVaultNamespace)
    .kmsProviders(kmsProviders)
    .build();
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()
    .keyVaultNamespace(keyVaultNamespace)
    .kmsProviders(kmsProviders)
    .schemaMap(new HashMap<String, BsonDocument>() {{
        put(dbName + "." + collName,
            // Need a schema that references the new data key
            BsonDocument.parse("{"
                + "  properties: {"
                + "    encryptedField: {"
                + "      encrypt: {"
                + "        keyId: [{"
                + "          \"$binary\": {"
                + "            \"base64\": \"" + base64DataKeyId + "\","
                + "            \"subType\": \"04\""
                + "          }"
                + "        }],"
                + "        bsonType: \"string\","
                + "        algorithm: \"AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic\""
                + "      }"
                + "    }"
                + "  },"
                + "  \"bsonType\": \"object\""
                + "}"));
}}).build();

Explicit Encryption and Decryption

Explicit encryption and decryption is a MongoDB community feature and does not use the mongocryptd process. Explicit encryption is provided by the ClientEncryption class.

The code example is from the ClientSideEncryptionExplicitEncryptionAndDecryptionTour.java file in the driver source code GitHub repository.

// 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);
    }});
}};
MongoNamespace keyVaultNamespace = new MongoNamespace("encryption.testKeyVault");
MongoClientSettings clientSettings = MongoClientSettings.builder().build();
MongoClient mongoClient = MongoClients.create(clientSettings);
// Set up the key vault for this example
MongoCollection<Document> keyVaultCollection = mongoClient
    .getDatabase(keyVaultNamespace.getDatabaseName())
    .getCollection(keyVaultNamespace.getCollectionName());
ObservableSubscriber<Void> successSubscriber = new OperationSubscriber<>();
keyVaultCollection.drop().subscribe(successSubscriber);
successSubscriber.await();
// Ensure that two data keys cannot share the same keyAltName.
ObservableSubscriber<String> indexSubscriber = new OperationSubscriber<>();
keyVaultCollection.createIndex(Indexes.ascending("keyAltNames"),
    new IndexOptions().unique(true)
        .partialFilterExpression(Filters.exists("keyAltNames")))
    .subscribe(indexSubscriber);
indexSubscriber.await();
MongoCollection<Document> collection = mongoClient.getDatabase("test").getCollection("coll");
successSubscriber = new OperationSubscriber<>();
collection.drop().subscribe(successSubscriber);
successSubscriber.await();
// Create the ClientEncryption instance
ClientEncryptionSettings clientEncryptionSettings = ClientEncryptionSettings.builder()
    .keyVaultMongoClientSettings(MongoClientSettings.builder()
        .applyConnectionString(new ConnectionString("mongodb://localhost"))
        .build())
    .keyVaultNamespace(keyVaultNamespace.getFullName())
    .kmsProviders(kmsProviders)
    .build();
ClientEncryption clientEncryption = ClientEncryptions.create(clientEncryptionSettings);
BsonBinary dataKeyId = clientEncryption.createDataKey("local", new DataKeyOptions());
// Explicitly encrypt a field
BsonBinary encryptedFieldValue = clientEncryption.encrypt(new BsonString("123456789"),
    new EncryptOptions("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").keyId(dataKeyId));
ObservableSubscriber<InsertOneResult> insertOneSubscriber = new OperationSubscriber<>();
collection.insertOne(new Document("encryptedField", encryptedFieldValue))
    .subscribe(insertOneSubscriber);
insertOneSubscriber.await();
ObservableSubscriber<Document> documentSubscriber = new OperationSubscriber<>();
collection.find().first().subscribe(documentSubscriber);
Document doc = documentSubscriber.get().get(0);
System.out.println(doc.toJson());
// Explicitly decrypt the field
System.out.println(
    clientEncryption.decrypt(new BsonBinary(doc.get("encryptedField", Binary.class).getData()))
);

Explicit Encryption and Auto Decryption

Although automatic encryption requires MongoDB 4.2 enterprise or a MongoDB 4.2 Atlas cluster, automatic decryption is supported for all users. To configure automatic decryption without automatic encryption, set bypassAutoEncryption(true).

The code example is from the ClientSideEncryptionExplicitEncryptionOnlyTour.java file in the driver source code GitHub repository.

...
MongoClientSettings clientSettings = MongoClientSettings.builder()
    .autoEncryptionSettings(AutoEncryptionSettings.builder()
        .keyVaultNamespace(keyVaultNamespace.getFullName())
        .kmsProviders(kmsProviders)
        .bypassAutoEncryption(true)
        .build())
    .build();
MongoClient mongoClient = MongoClients.create(clientSettings);
...
// Explicitly encrypt a field
BsonBinary encryptedFieldValue = clientEncryption.encrypt(new BsonString("123456789"),
    new EncryptOptions("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").keyId(dataKeyId));
ObservableSubscriber<InsertOneResult> insertOneSubscriber = new OperationSubscriber<>();
collection.insertOne(new Document("encryptedField", encryptedFieldValue))
    .subscribe(insertOneSubscriber);
insertOneSubscriber.await();
ObservableSubscriber<Document> documentSubscriber = new OperationSubscriber<>();
collection.find().first().subscribe(documentSubscriber);
Document doc = documentSubscriber.get().get(0);
System.out.println(doc.toJson());

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