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Explicit Encryption

On this page

  • Overview
  • Use Explicit Encryption
  • Create a ClientEncryption Instance
  • Encrypt Fields in Read and Write Operations
  • Manual Decryption
  • Automatic Decryption
  • Example
  • Create a MongoClient Instance
  • Create a ClientEncryption Instance
  • Encrypt Fields and Insert
  • Retrieve Document and Decrypt Fields
  • Server-Side Field Level Encryption Enforcement
  • Learn More

Learn how to use the explicit encryption mechanism of Client-Side Field Level Encryption (CSFLE).

Explicit encryption is a mechanism in which you specify how to encrypt and decrypt fields in your document for each operation you perform on your database.

Explicit encryption is available in the following MongoDB products of version 4.2 or later:

  • MongoDB Community Server

  • MongoDB Enterprise Advanced

  • MongoDB Atlas

To use explicit encryption you must perform the following actions in your CSFLE-enabled application:

  • Create a ClientEncryption Instance

  • Encrypt Fields in Read and Write Operations

  • Manually or Automatically Decrypt Fields in Your Documents

To use explicit encryption, you must create a ClientEncryption instance. ClientEncryption is an abstraction used across drivers and mongosh that encapsulates the Key Vault collection and KMS operations involved in explicit encryption.

To create a ClientEncryption instance, you must specify the following information:

  • A MongoClient instance with access to your Key Vault collection

  • The namespace of your Key Vault collection

  • A kmsProviders object configured with access to the KMS provider hosting your Customer Master Key

For more ClientEncryption options, see CSFLE-Specific MongoClient Options.

To view code snippets that show how to create a ClientEncryption instance, see the Example section of this guide.

You must update read and write operations throughout your application such that your application encrypts fields before performing read and write operations.

To encrypt fields, use the encrypt method of your ClientEncryption instance.

To view code snippets that show how to use the encrypt method, see the Example section of this guide.

You can decrypt your encrypted fields manually or automatically when using explicit encryption.

To decrypt your fields manually, use the decrypt method of your ClientEncryption instance.

To view code snippets that show how to use the decrypt method, see the Example section of this guide.

To decrypt your fields automatically, configure your MongoClient instance as follows:

  • Specify your Key Vault collection

  • Specify a kmsProviders object

  • If you use MongoDB Community Server, set the bypassAutoEncryption option to True

Note

Automatic Decryption is Available in MongoDB Community Server

Although automatic encryption requires MongoDB Enterprise or MongoDB Atlas, automatic decryption is available in the following MongoDB products:

  • MongoDB Community Server

  • MongoDB Enterprise Advanced

  • MongoDB Atlas

To view a code snippet demonstrating how to enable automatic decryption, select the tab corresponding to your preferred language:

var autoEncryptionOpts = {
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders,
bypassAutoEncryption: true,
};
var encryptedClient = Mongo(
connectionString,
autoEncryptionOpts
);
var clientSettings = MongoClientSettings.FromConnectionString(connectionString);
var autoEncryptionOptions = new AutoEncryptionOptions(
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders,
bypassAutoEncryption: true);
clientSettings.AutoEncryptionOptions = autoEncryptionOptions;
var client = new MongoClient(clientSettings);
autoEncryptionOpts := options.AutoEncryption().
SetKmsProviders(kmsProviders).
SetKeyVaultNamespace(KeyVaultNamespace).
SetBypassAutoEncryption(true)
client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(URI).SetAutoEncryptionOptions(autoEncryptionOpts))
if err != nil {
return fmt.Errorf("Connect error for encrypted client: %v", err)
}
defer func() {
_ = client.Disconnect(context.TODO())
}()
MongoClientSettings clientSettings = MongoClientSettings.builder()
.applyConnectionString(new ConnectionString(connectionString))
.autoEncryptionSettings(AutoEncryptionSettings.builder()
.keyVaultNamespace(keyVaultNamespace)
.kmsProviders(kmsProviders).bypassAutoEncryption(true)
.build())
.build();
MongoClient mongoClient = MongoClients.create(clientSettings);
const client = new MongoClient(connectionString, {
useNewUrlParser: true,
useUnifiedTopology: true,
monitorCommands: true,
autoEncryption: {
keyVaultNamespace,
kmsProviders,
bypassAutoEncryption: true,
},
});
auto_encryption_opts = AutoEncryptionOpts(
kms_providers=kms_providers,
key_vault_namespace=key_vault_namespace,
bypass_auto_encryption=True,
)
client = MongoClient(auto_encryption_opts=auto_encryption_opts)

Assume you want to insert documents with the following structure into your MongoDB instance:

{
"name": "<name of person>",
"age": <age of person>,
"favorite-foods": ["<array of foods>"]
}
1

In this example, you use the same MongoClient instance to access your Key Vault collection and to read and write encrypted data.

The following code snippets show how to create a MongoClient instance:

const autoEncryptionOpts = {
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders,
};
const encryptedClient = Mongo(connectionString, autoEncryptionOpts);
var client = new MongoClient(connectionString);
client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(URI))
if err != nil {
panic(fmt.Errorf("Client connect error %v", err))
}
MongoClient client = MongoClients.create(connectionString);
const client = new MongoClient(connectionString, {
useNewUrlParser: true,
useUnifiedTopology: true,
});
client = MongoClient(your_connection_uri)
2

The following code snippets show how to create a ClientEncryption instance:

const clientEncryption = encryptedClient.getClientEncryption();
var collection = client.GetDatabase(db).GetCollection<BsonDocument>(coll);
var clientEncryptionOptions = new ClientEncryptionOptions(
keyVaultClient: client,
keyVaultNamespace: keyVaultNamespace,
kmsProviders: kmsProviders);
var clientEncryption = new ClientEncryption(clientEncryptionOptions);
coll := client.Database(DbName).Collection(CollName)
clientEncryptionOpts := options.ClientEncryption().SetKeyVaultNamespace(KeyVaultNamespace).SetKmsProviders(kmsProviders)
clientEnc, err := mongo.NewClientEncryption(client, clientEncryptionOpts)
if err != nil {
panic(fmt.Errorf("NewClientEncryption error %v", err))
}
defer func() {
_ = clientEnc.Close(context.TODO())
}()
MongoCollection<Document> collection = client.getDatabase(db).getCollection(coll);
ClientEncryptionSettings clientEncryptionSettings = ClientEncryptionSettings.builder()
.keyVaultMongoClientSettings(MongoClientSettings.builder()
.applyConnectionString(new ConnectionString(connectionString))
.build())
.keyVaultNamespace(keyVaultNamespace)
.kmsProviders(kmsProviders)
.build();
ClientEncryption clientEncryption = ClientEncryptions.create(clientEncryptionSettings);
const collection = client.db(db).collection(coll);
const encryption = new ClientEncryption(client, {
keyVaultNamespace,
kmsProviders,
});
coll = client.employees.foods
client_encryption = ClientEncryption(
kms_providers,
"encryption.___keyVault",
client,
coll.codec_options,
)

Note

CodecOptions

The MongoDB Python driver requires that you specify the CodecOptions with which you would like to encrypt and decrypt your documents.

Specify the CodecOptions you have configured on the MongoClient, Database, or Collection with which you are writing encrypted and decrypted application data to MongoDB.

3

You want to encrypt the fields of your document using the following algorithms:

Field Name
Encryption Algorithm
BSON Type of Field
name
Deterministic
String
age
No encryption
Int
favorite-foods
Random
Array

The following code snippets show how to manually encrypt the fields in your document and insert your document into MongoDB:

Note

The dataKeyId variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

const encName = clientEncryption.encrypt(
dataKeyId,
"Greg",
"AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"
);
const encFoods = clientEncryption.encrypt(
dataKeyId,
["Cheese", "Grapes"],
"AEAD_AES_256_CBC_HMAC_SHA_512-Random"
);
db.getSiblingDB(database).getCollection(collection).insertOne({
name: encName,
foods: encFoods,
});

Note

The dataKeyId variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

var encryptedName = clientEncryption.Encrypt(
"Greg",
new EncryptOptions(algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic", keyId: dataKeyId),
CancellationToken.None);
var encryptedFoods = clientEncryption.Encrypt(
new BsonArray { "Cheese", "Grapes" },
new EncryptOptions(algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Random", keyId: dataKeyId),
CancellationToken.None);
collection.InsertOne(new BsonDocument { { "name", encryptedName }, { "age", 83 }, { "foods", encryptedFoods } });

Note

The dataKeyId variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

nameRawValueType, nameRawValueData, err := bson.MarshalValue("Greg")
if err != nil {
panic(err)
}
nameRawValue := bson.RawValue{Type: nameRawValueType, Value: nameRawValueData}
nameEncryptionOpts := options.Encrypt().
SetAlgorithm("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").
SetKeyID(dataKeyId)
nameEncryptedField, err := clientEnc.Encrypt(
context.TODO(),
nameRawValue,
nameEncryptionOpts)
if err != nil {
panic(err)
}
foodsRawValueType, foodsRawValueData, err := bson.MarshalValue(bson.A{"Grapes", "Cheese"})
if err != nil {
panic(err)
}
foodsRawValue := bson.RawValue{Type: foodsRawValueType, Value: foodsRawValueData}
encryptionOpts := options.Encrypt().
SetAlgorithm("AEAD_AES_256_CBC_HMAC_SHA_512-Random").
SetKeyID(dataKeyId)
foodsEncryptedField, err := clientEnc.Encrypt(
context.TODO(),
foodsRawValue,
encryptionOpts)
if err != nil {
panic(err)
}
_, err = coll.InsertOne(
context.TODO(),
bson.D{{"name", nameEncryptedField}, {"foods", foodsEncryptedField}, {"age", 83}})
if err != nil {
panic(err)
}

Note

The dataKeyId variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

BsonBinary encryptedName = clientEncryption.encrypt(new BsonString("Greg"), new EncryptOptions("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").keyId(dataKeyId));
BsonBinary encryptedFoods = clientEncryption.encrypt(new BsonArray().parse("[\"Grapes\", \"Foods\"]"), new EncryptOptions("AEAD_AES_256_CBC_HMAC_SHA_512-Random").keyId(dataKeyId));
collection.insertOne(new Document("name", encryptedName).append("foods", encryptedFoods).append("age", 83));

Note

The dataKeyId variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

encryptedName = await encryption.encrypt("Greg", {
algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
keyId: dataKeyId,
});
encryptedFoods = await encryption.encrypt(["Cheese", "Grapes"], {
algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Random",
keyId: dataKeyId,
});
await collection.insertOne({
name: encryptedName,
age: 83,
foods: encryptedFoods,
});

Note

The data_key_id variable in the following examples refers to a Data Encryption Key (DEK). To learn how to generate a DEK with your Local Key Provider, see the Quick Start. To learn how to create a DEK with a specific Key Management System, see Tutorials.

encrypted_name = client_encryption.encrypt(
"Greg",
Algorithm.AEAD_AES_256_CBC_HMAC_SHA_512_Deterministic,
key_id=data_key_id,
)
encrypted_foods = client_encryption.encrypt(
["Cheese", "Grapes"],
Algorithm.AEAD_AES_256_CBC_HMAC_SHA_512_Random,
key_id=data_key_id,
)
coll.insert_one({"name": encrypted_name, "age": 83, "foods": encrypted_foods})
4

The following code snippets show how to retrieve your inserted document and manually decrypt the encrypted fields:

const encNameQuery = clientEncryption.encrypt(
dataKeyId,
"Greg",
"AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"
);
let doc = db.getSiblingDB(database).getCollection(collection).findOne({
name: encNameQuery,
});
console.log(doc);
doc.name = clientEncryption.decrypt(doc.name);
doc.foods = clientEncryption.decrypt(doc.foods);
console.log(doc);
var nameToQuery = "Greg";
var encryptedNameToQuery = clientEncryption.Encrypt(
nameToQuery,
new EncryptOptions(algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic", keyId: dataKeyId),
CancellationToken.None);
var doc = collection.Find(new BsonDocument { { "name", encryptedNameToQuery } }).Single();
Console.WriteLine($"Encrypted document: {doc}");
doc["name"] = clientEncryption.Decrypt(doc["name"].AsBsonBinaryData, CancellationToken.None);
doc["foods"] = clientEncryption.Decrypt(doc["foods"].AsBsonBinaryData, CancellationToken.None);
Console.WriteLine($"Decrypted field: {doc}");
nameQueryRawValueType, nameQueryRawValueData, err := bson.MarshalValue("Greg")
if err != nil {
panic(err)
}
nameQueryRawValue := bson.RawValue{Type: nameQueryRawValueType, Value: nameQueryRawValueData}
nameQueryEncryptionOpts := options.Encrypt().
SetAlgorithm("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").
SetKeyID(dataKeyId)
nameQueryEncryptedField, err := clientEnc.Encrypt(
context.TODO(),
nameQueryRawValue,
nameQueryEncryptionOpts)
if err != nil {
panic(err)
}
var result bson.M
err = coll.FindOne(
context.TODO(),
bson.D{{"name", nameQueryEncryptedField}}).Decode(&result)
if err != nil {
if err == mongo.ErrNoDocuments {
return
}
panic(err)
}
fmt.Printf("Encrypted Document: %s\n", result)
nameDecrypted, err := clientEnc.Decrypt(
context.TODO(),
result["name"].(primitive.Binary))
foodsDecrypted, err := clientEnc.Decrypt(
context.TODO(),
result["foods"].(primitive.Binary))
result["foods"] = foodsDecrypted
result["name"] = nameDecrypted
fmt.Printf("Decrypted Document: %s\n", result)
BsonBinary encryptedNameQuery = clientEncryption.encrypt(new BsonString("Greg"), new EncryptOptions("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic").keyId(dataKeyId));
Document result = collection.find(eq("name", encryptedNameQuery)).first();
System.out.println("Encrypted Document: " + result.toJson());
result.replace("name", clientEncryption.decrypt(new BsonBinary(result.get("name", Binary.class).getData())));
result.replace("foods", clientEncryption.decrypt(new BsonBinary(result.get("foods", Binary.class).getData())));
System.out.println("Decrypted Document: " + result.toJson());
queryEncryptedName = await encryption.encrypt("Greg", {
algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
keyId: dataKeyId,
});
let doc = await collection.findOne({ name: queryEncryptedName });
console.log("Encrypted Document: ", doc);
doc.name = encryption.decrypt(doc.name);
doc.foods = encryption.decrypt(doc.foods);
console.log("Decrypted document: ", doc);
name_to_query = "Greg"
encrypted_name_to_query = client_encryption.encrypt(
name_to_query,
Algorithm.AEAD_AES_256_CBC_HMAC_SHA_512_Deterministic,
key_id=data_key_id,
)
doc = client.employees.foods.find_one({"name": encrypted_name_to_query})
print("Encrypted document: %s" % (doc,))
doc["name"] = client_encryption.decrypt(doc["name"])
doc["foods"] = client_encryption.decrypt(doc["foods"])
print("Decrypted document: %s" % (doc,))

MongoDB supports using schema validation to enforce encryption of specific fields in a collection.

A client performing Client-Side Field Level Encryption with the explicit encryption mechanism on a MongoDB instance configured to enforce encryption of certain fields must encrypt those fields as specified on the MongoDB instance.

To learn how to set up server-side CSFLE enforcement, see CSFLE Server-Side Schema Enforcement.

To learn more about Key Vault collections, Data Encryption Keys, and Customer Master Keys, see Keys and Key Vaults.

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

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Encryption Schemas