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Client-Side Field Level Encryption

Quick Start

On this page

  • Overview
  • Before You Get Started
  • Procedure
  • Create a Customer Master Key
  • Create a Unique Index on your Key Vault collection
  • Create a Data Encryption Key
  • Configure the MongoClient
  • Insert a Document with Encrypted Fields
  • Retrieve Your Document with Encrypted Fields
  • Learn More

Overview

This guide shows you how to encrypt a document with automatic Client-Side Field Level Encryption (CSFLE) and a MongoDB driver.

After completing this guide, you should have the following knowledge and software:

  • Knowledge of the steps to configure a driver to encrypt fields in a document.

  • A working, but not production-ready, client application that utilizes automatic Client-Side Field Level Encryption.

Important

Do Not Use this Application In Production

Since this example application stores an encryption key on your application's filesystem, you risk unauthorized access to the key or loss of the key to decrypt your data.

To view a tutorial that demonstrates how to create a production-ready CSFLE-enabled application, see Tutorials.

Before You Get Started

To complete and run the code in this guide, you need to set up your development environment as shown in the Installation Requirements page.

Select the programming language for which you want to see code examples for from the Select your language dropdown menu on the right side of the page.

Tip

See: Full Application

To view the complete runnable application code for this tutorial, go to the following link:

Complete C# Application

Procedure

// You are viewing the C# driver code examples.
// Use the dropdown menu to select a different driver.
// You are viewing the Golang driver code examples.
// Use the dropdown menu to select a different driver.

Important

When building or running the Golang code in this guide using go build or go run, always include the cse build constraint to enable CSFLE. See the following shell command for an example of including the build constraint:

go run -tags cse insert-encrypted-document.go
// You are viewing the Java synchronous driver code examples.
// Use the dropdown menu to select a different driver.
// You are viewing the Node.js driver code examples.
// Use the dropdown menu to select a different driver.
# You are viewing the Python driver code examples.
# Use the dropdown menu to select a different driver.
1

Create a Customer Master Key

You must create a Customer Master Key (CMK) to perform CSFLE.

Create a 96-byte Customer Master Key and save it in your Local Key Provider, which is your filesystem, as the file master-key.txt:

const fs = require("fs");
const crypto = require("crypto");
try {
  fs.writeFileSync("master-key.txt", crypto.randomBytes(96));
} catch (err) {
  console.error(err);
}
using (var randomNumberGenerator = System.Security.Cryptography.RandomNumberGenerator.Create())
{
    var bytes = new byte[96];
    randomNumberGenerator.GetBytes(bytes);
    var localMasterKeyBase64Write = Convert.ToBase64String(bytes);
    Console.WriteLine(localMasterKeyBase64Write);
    File.WriteAllText("master-key.txt", localMasterKeyBase64Write);
}
func localMasterKey() []byte {
	key := make([]byte, 96)
	if _, err := rand.Read(key); err != nil {
		log.Fatalf("Unable to create a random 96 byte data key: %v", err)
	}
	if err := ioutil.WriteFile("master-key.txt", key, 0644); err != nil {
		log.Fatalf("Unable to write key to file: %v", err)
	}
	return key
}
byte[] localMasterKeyWrite = new byte[96];
new SecureRandom().nextBytes(localMasterKeyWrite);
try (FileOutputStream stream = new FileOutputStream("master-key.txt")) {
    stream.write(localMasterKeyWrite);
}
import os
path = "master-key.txt"
file_bytes = os.urandom(96)
with open(path, "wb") as f:
    f.write(file_bytes)

Warning

Do Not Use the Local Key Provider in Production

The Local Key Provider is an insecure method of storage and is not recommended for production. Instead, you should store your Customer Master Keys in a remote Key Management System (KMS).

To learn how to use a remote KMS in your CSFLE implementation, see the Tutorials guide.

Tip

Generate a CMK from the Command Line

Use the following command to generate a CMK from a Unix shell or PowerShell:

  • Unix shell:

    echo $(head -c 96 /dev/urandom | base64 | tr -d '\n')

  • PowerShell:

    $r=[byte[]]::new(64);$g=[System.Security.Cryptography.RandomNumberGenerator]::Create();$g.GetBytes($r);[Convert]::ToBase64String($r)

Save the output of the preceding command to a file named customer-master-key.txt.

Tip

See: Complete Code

To view the complete code for making a Customer Master Key, see our Github repository.

To view the complete code for making a Customer Master Key, see our Github repository.

To view the complete code for making a Customer Master Key, see our Github repository.

To view the complete code for making a Customer Master Key, see our Github repository.

To view the complete code for making a Customer Master Key, see our Github repository.

2

Create a Unique Index on your Key Vault collection

Create a partial unique index on the keyAltNames field in your encryption.__keyVault namespace. 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.

Select the tab corresponding to your preferred MongoDB driver:

var connectionString = "<Your MongoDB URI>";
var keyVaultNamespace = CollectionNamespace.FromFullName("encryption.__keyVault");
var keyVaultClient = new MongoClient(connectionString);
var indexOptions = new CreateIndexOptions<BsonDocument>();
indexOptions.Unique = true;
indexOptions.PartialFilterExpression = new BsonDocument { { "keyAltNames", new BsonDocument { { "$exists", new BsonBoolean(true) } } } };
var builder = Builders<BsonDocument>.IndexKeys;
var indexKeysDocument = builder.Ascending("keyAltNames");
var indexModel = new CreateIndexModel<BsonDocument>(indexKeysDocument, indexOptions);
var keyVaultDatabase = keyVaultClient.GetDatabase(keyVaultNamespace.DatabaseNamespace.ToString());
// Drop the Key Vault Collection in case you created this collection
// in a previous run of this application.  
keyVaultDatabase.DropCollection(keyVaultNamespace.CollectionName);
// Drop the database storing your encrypted fields as all
// the DEKs encrypting those fields were deleted in the preceding line.
keyVaultClient.GetDatabase("medicalRecords").DropCollection("patients");
var keyVaultCollection = keyVaultDatabase.GetCollection<BsonDocument>(keyVaultNamespace.CollectionName.ToString());
keyVaultCollection.Indexes.CreateOne(indexModel);
uri := "<Your MongoDB URI>"
keyVaultClient, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(uri))
if err != nil {
	return fmt.Errorf("Connect error for regular client: %v", err)
}
defer func() {
	_ = keyVaultClient.Disconnect(context.TODO())
}()
keyVaultColl := "__keyVault"
keyVaultDb := "encryption"
keyVaultNamespace := keyVaultDb + "." + keyVaultColl
keyVaultIndex := mongo.IndexModel{
	Keys: bson.D{{"keyAltNames", 1}},
	Options: options.Index().
		SetUnique(true).
		SetPartialFilterExpression(bson.D{
			{"keyAltNames", bson.D{
				{"$exists", true},
			}},
		}),
}
// Drop the Key Vault Collection in case you created this collection
// in a previous run of this application.
if err = keyVaultClient.Database(keyVaultDb).Collection(keyVaultColl).Drop(context.TODO()); err != nil {
	log.Fatalf("Collection.Drop error: %v", err)
}
// Drop the database storing your encrypted fields as all
// the DEKs encrypting those fields were deleted in the preceding line.
if err = keyVaultClient.Database("medicalRecords").Collection("patients").Drop(context.TODO()); err != nil {
	log.Fatalf("Collection.Drop error: %v", err)
}
_, err = keyVaultClient.Database(keyVaultDb).Collection(keyVaultColl).Indexes().CreateOne(context.TODO(), keyVaultIndex)
if err != nil {
	panic(err)
}
String connectionString = "<Your MongoDB URI>";
String keyVaultDb = "encryption";
String keyVaultColl = "__keyVault";
String keyVaultNamespace = keyVaultDb + "." + keyVaultColl;
MongoClient keyVaultClient = MongoClients.create(connectionString);
// Drop the Key Vault Collection in case you created this collection
// in a previous run of this application.
keyVaultClient.getDatabase(keyVaultDb).getCollection(keyVaultColl).drop();
// Drop the database storing your encrypted fields as all
// the DEKs encrypting those fields were deleted in the preceding line.
keyVaultClient.getDatabase("medicalRecords").getCollection("patients").drop();
MongoCollection keyVaultCollection = keyVaultClient.getDatabase(keyVaultDb).getCollection(keyVaultColl);
IndexOptions indexOpts = new IndexOptions().partialFilterExpression(new BsonDocument("keyAltNames", new BsonDocument("$exists", new BsonBoolean(true) ))).unique(true);
keyVaultCollection.createIndex(new BsonDocument("keyAltNames", new BsonInt32(1)), indexOpts);
keyVaultClient.close();
const uri = "<Your Connection String>";
const keyVaultDatabase = "encryption";
const keyVaultCollection = "__keyVault";
const keyVaultNamespace = `${keyVaultDatabase}.${keyVaultCollection}`;
const keyVaultClient = new MongoClient(uri);
await keyVaultClient.connect();
const keyVaultDB = keyVaultClient.db(keyVaultDatabase);
// Drop the Key Vault Collection in case you created this collection
// in a previous run of this application.
await keyVaultDB.dropDatabase();
// Drop the database storing your encrypted fields as all
// the DEKs encrypting those fields were deleted in the preceding line.
await keyVaultClient.db("medicalRecords").dropDatabase();
const keyVaultColl = keyVaultDB.collection(keyVaultCollection);
await keyVaultColl.createIndex(
  { keyAltNames: 1 },
  {
    unique: true,
    partialFilterExpression: { keyAltNames: { $exists: true } },
  }
);
connection_string = "<your connection string here>"
key_vault_coll = "__keyVault"
key_vault_db = "encryption"
key_vault_namespace = f"{key_vault_db}.{key_vault_coll}"
key_vault_client = MongoClient(connection_string)
# Drop the Key Vault Collection in case you created this collection
# in a previous run of this application.
key_vault_client.drop_database(key_vault_db)
# Drop the database storing your encrypted fields as all
# the DEKs encrypting those fields were deleted in the preceding line.
key_vault_client["medicalRecords"].drop_collection("patients")
key_vault_client[key_vault_db][key_vault_coll].create_index(
    [("keyAltNames", ASCENDING)],
    unique=True,
    partialFilterExpression={"keyAltNames": {"$exists": True}},
)
3

Create a Data Encryption Key

1

Read the Customer Master Key and Specify KMS Provider Settings

Retrieve the contents of the Customer Master Key file that you generated in the Create a Customer Master Key step of this guide.

Pass the CMK value to your KMS provider settings. The client uses these settings to discover the CMK. As you are using the Local Key Provider, set the provider name to local.

var kmsProviders = new Dictionary<string, IReadOnlyDictionary<string, object>>();
var provider = "local";
string localMasterKeyBase64Read = File.ReadAllText("master-key.txt");
var localMasterKeyBytes = Convert.FromBase64String(localMasterKeyBase64Read);
var localOptions = new Dictionary<string, object>
{
    { "key", localMasterKeyBytes }
};
kmsProviders.Add("local", localOptions);
key, err := ioutil.ReadFile("master-key.txt")
if err != nil {
	log.Fatalf("Could not read the key from master-key.txt: %v", err)
}
provider := "local"
kmsProviders := map[string]map[string]interface{}{"local": {"key": key}}
String kmsProvider = "local";
String path = "master-key.txt";
byte[] localMasterKeyRead = new byte[96];
try (FileInputStream fis = new FileInputStream(path)) {
    if (fis.read(localMasterKeyRead) < 96)
        throw new Exception("Expected to read 96 bytes from file");
}
Map<String, Object> keyMap = new HashMap<String, Object>();
keyMap.put("key", localMasterKeyRead);
Map<String, Map<String, Object>> kmsProviders = new HashMap<String, Map<String, Object>>();
kmsProviders.put("local", keyMap);
const provider = "local";
const path = "./master-key.txt";
const localMasterKey = fs.readFileSync(path);
const kmsProviders = {
  local: {
    key: localMasterKey,
  },
};
path = "./master-key.txt"
with open(path, "rb") as f:
    local_master_key = f.read()
kms_providers = {
    "local": {
        "key": local_master_key  # local_master_key variable from the previous step
    },
}
2

Create a Data Encryption Key

Construct a client with your MongoDB connection string and Key Vault collection namespace, and create a Data Encryption Key:

Note

Key Vault Collection Namespace Permissions

To complete this tutorial, the database user your application uses to connect to MongoDB must have dbAdmin permissions on the following namespaces:

  • encryption.__keyVault

  • medicalRecords database

var clientEncryptionOptions = new ClientEncryptionOptions(
    keyVaultClient: keyVaultClient,
    keyVaultNamespace: keyVaultNamespace,
    kmsProviders: kmsProviders
    );
var clientEncryption = new ClientEncryption(clientEncryptionOptions);
var dataKeyOptions = new DataKeyOptions();
var dataKeyId = clientEncryption.CreateDataKey(provider, dataKeyOptions, CancellationToken.None);
var dataKeyIdBase64 = Convert.ToBase64String(GuidConverter.ToBytes(dataKeyId, GuidRepresentation.Standard));
Console.WriteLine($"DataKeyId [base64]: {dataKeyIdBase64}");
clientEncryptionOpts := options.ClientEncryption().SetKeyVaultNamespace(keyVaultNamespace).
	SetKmsProviders(kmsProviders)
clientEnc, err := mongo.NewClientEncryption(keyVaultClient, clientEncryptionOpts)
if err != nil {
	return fmt.Errorf("NewClientEncryption error %v", err)
}
defer func() {
	_ = clientEnc.Close(context.TODO())
}()
dataKeyOpts := options.DataKey()
dataKeyID, err := clientEnc.CreateDataKey(context.TODO(), provider, dataKeyOpts)
if err != nil {
	return fmt.Errorf("create data key error %v", err)
}
fmt.Printf("DataKeyId [base64]: %s\n", base64.StdEncoding.EncodeToString(dataKeyID.Data))
ClientEncryptionSettings clientEncryptionSettings = ClientEncryptionSettings.builder()
        .keyVaultMongoClientSettings(MongoClientSettings.builder()
                .applyConnectionString(new ConnectionString(connectionString))
                .build())
        .keyVaultNamespace(keyVaultNamespace)
        .kmsProviders(kmsProviders)
        .build();
MongoClient regularClient = MongoClients.create(connectionString);
ClientEncryption clientEncryption = ClientEncryptions.create(clientEncryptionSettings);
BsonBinary dataKeyId = clientEncryption.createDataKey(kmsProvider, new DataKeyOptions());
String base64DataKeyId = Base64.getEncoder().encodeToString(dataKeyId.getData());
System.out.println("DataKeyId [base64]: " + base64DataKeyId);
clientEncryption.close();
const client = new MongoClient(uri, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});
await client.connect();
const encryption = new ClientEncryption(client, {
  keyVaultNamespace,
  kmsProviders,
});
const key = await encryption.createDataKey(provider);
console.log("DataKeyId [base64]: ", key.toString("base64"));
await keyVaultClient.close();
await client.close();

Note

Import ClientEncryption

When using the Node.js driver v6.0 and later, you must import ClientEncryption from mongodb.

For earlier driver versions, import ClientEncryption from mongodb-client-encryption.

key_vault_database = "encryption"
key_vault_collection = "__keyVault"
key_vault_namespace = f"{key_vault_database}.{key_vault_collection}"
client = MongoClient(connection_string)
client_encryption = ClientEncryption(
    kms_providers,  # pass in the kms_providers variable from the previous step
    key_vault_namespace,
    client,
    CodecOptions(uuid_representation=STANDARD),
)
data_key_id = client_encryption.create_data_key("local")
base_64_data_key_id = base64.b64encode(data_key_id)
print("DataKeyId [base64]: ", base_64_data_key_id)

The output from the code above should resemble the following:

DataKeyId [base64]: 3k13WkSZSLy7kwAAP4HDyQ==

Tip

See: Complete Code

To view the complete code for making a Data Encryption Key, see our Github repository.

To view the complete code for making a Data Encryption Key, see our Github repository.

To view the complete code for making a Data Encryption Key, see our Github repository.

To view the complete code for making a Data Encryption Key, see our Github repository.

To view the complete code for making a Data Encryption Key, see our Github repository.

4

Configure the MongoClient

1

Specify the Key Vault Collection Namespace

Specify encryption.__keyVault as the Key Vault collection namespace.

var keyVaultNamespace = CollectionNamespace.FromFullName("encryption.__keyVault");
keyVaultNamespace := "encryption.__keyVault"
String keyVaultNamespace = "encryption.__keyVault";
const keyVaultNamespace = "encryption.__keyVault";
key_vault_namespace = "encryption.__keyVault"
2

Specify the Local Customer Master Key

Specify the KMS provider and specify your key inline:

var kmsProviders = new Dictionary<string, IReadOnlyDictionary<string, object>>();
var provider = "local";
var localMasterKeyPath = "master-key.txt";
string localMasterKeyBase64Read = File.ReadAllText(localMasterKeyPath);
var localMasterKeyBytes = Convert.FromBase64String(localMasterKeyBase64Read);
var localOptions = new Dictionary<string, object>
{
    { "key", localMasterKeyBytes }
};
kmsProviders.Add(provider, localOptions);
key, err := ioutil.ReadFile("master-key.txt")
if err != nil {
	log.Fatalf("Could not read the key from master-key.txt: %v", err)
}
kmsProviders := map[string]map[string]interface{}{"local": {"key": key}}
String kmsProvider = "local";
String path = "master-key.txt";
byte[] localMasterKeyRead = new byte[96];
try (FileInputStream fis = new FileInputStream(path)) {
    if (fis.read(localMasterKeyRead) < 96)
        throw new Exception("Expected to read 96 bytes from file");
}
Map<String, Object> keyMap = new HashMap<String, Object>();
keyMap.put("key", localMasterKeyRead);
Map<String, Map<String, Object>> kmsProviders = new HashMap<String, Map<String, Object>>();
kmsProviders.put("local", keyMap);
const fs = require("fs");
const provider = "local";
const path = "./master-key.txt";
const localMasterKey = fs.readFileSync(path);
const kmsProviders = {
  local: {
    key: localMasterKey,
  },
};
path = "./master-key.txt"
with open(path, "rb") as f:
    local_master_key = f.read()
kms_providers = {
    "local": {
        "key": local_master_key  # local_master_key variable from the previous step
    },
}
3

Create an Encryption Schema For Your Collection

Tip

Add Your Data Encryption Key Base64 ID

Make sure to update the following code to include your Base64 DEK ID. You received this value in the Generate your Data Encryption Key step of this guide.

var keyId = "<Your base64 DEK ID here>";
var schema = new BsonDocument
{
   { "bsonType", "object" },
   {
       "encryptMetadata",
       new BsonDocument("keyId", new BsonArray(new[] { new BsonBinaryData(Convert.FromBase64String(keyId), BsonBinarySubType.UuidStandard) }))
   },
   {
       "properties",
       new BsonDocument
       {
           {
               "ssn", new BsonDocument
               {
                   {
                       "encrypt", new BsonDocument
                       {
                           { "bsonType", "int" },
                           { "algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic" }
                       }
                   }
               }
           },
           {
               "bloodType", new BsonDocument
               {
                   {
                       "encrypt", new BsonDocument
                       {
                           { "bsonType", "string" },
                           { "algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Random" }
                       }
                   }
               }
           },
           {
               "medicalRecords", new BsonDocument
               {
                   {
                       "encrypt", new BsonDocument
                       {
                           { "bsonType", "array" },
                           { "algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Random" }
                       }
                   }
               }
           },
           {
               "insurance", new BsonDocument
               {
                   { "bsonType", "object" },
                   {
                       "properties", new BsonDocument
                       {
                           {
                               "policyNumber", new BsonDocument
                               {
                                   {
                                       "encrypt", new BsonDocument
                                       {
                                           { "bsonType", "int" },
                                           { "algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic" }
                                       }
                                   }
                               }
                           }
                       }
                   }
               }
           }
       }
   }
};
var schemaMap = new Dictionary<string, BsonDocument>();
schemaMap.Add(dbNamespace, schema);
dek_id := "<Your Base64 DEK ID>"
schema_template := `{
	"bsonType": "object",
	"encryptMetadata": {
		"keyId": [
			{
				"$binary": {
					"base64": "%s",
					"subType": "04"
				}
			}
		]
	},
	"properties": {
		"insurance": {
			"bsonType": "object",
			"properties": {
				"policyNumber": {
					"encrypt": {
						"bsonType": "int",
						"algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"
					}
				}
			}
		},
		"medicalRecords": {
			"encrypt": {
				"bsonType": "array",
				"algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
			}
		},
		"bloodType": {
			"encrypt": {
				"bsonType": "string",
				"algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
			}
		},
		"ssn": {
			"encrypt": {
				"bsonType": "int",
				"algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"
			}
		}
	}
}`
schema := fmt.Sprintf(schema_template, dek_id)
var schemaDoc bson.Raw
if err := bson.UnmarshalExtJSON([]byte(schema), true, &schemaDoc); err != nil {
	return fmt.Errorf("UnmarshalExtJSON error: %v", err)
}
schemaMap := map[string]interface{}{
	dbName + "." + collName: schemaDoc,
}
String dekId = "<paste-base-64-encoded-data-encryption-key-id>>";
Document jsonSchema = new Document().append("bsonType", "object").append("encryptMetadata",
        new Document().append("keyId", new ArrayList<>((Arrays.asList(new Document().append("$binary", new Document()
                .append("base64", dekId)
                .append("subType", "04")))))))
        .append("properties", new Document()
                .append("ssn", new Document().append("encrypt", new Document()
                        .append("bsonType", "int")
                        .append("algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic")))
                .append("bloodType", new Document().append("encrypt", new Document()
                        .append("bsonType", "string")
                        .append("algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Random")))
                .append("medicalRecords", new Document().append("encrypt", new Document()
                        .append("bsonType", "array")
                        .append("algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Random")))
                .append("insurance", new Document()
                        .append("bsonType", "object")
                        .append("properties",
                                new Document().append("policyNumber", new Document().append("encrypt", new Document()
                                        .append("bsonType", "int")
                                        .append("algorithm", "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"))))));
HashMap<String, BsonDocument> schemaMap = new HashMap<String, BsonDocument>();
schemaMap.put("medicalRecords.patients", BsonDocument.parse(jsonSchema.toJson()));
dataKey = "<Your base64 DEK ID>";
const schema = {
  bsonType: "object",
  encryptMetadata: {
    keyId: [new Binary(Buffer.from(dataKey, "base64"), 4)],
  },
  properties: {
    insurance: {
      bsonType: "object",
      properties: {
        policyNumber: {
          encrypt: {
            bsonType: "int",
            algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
          },
        },
      },
    },
    medicalRecords: {
      encrypt: {
        bsonType: "array",
        algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Random",
      },
    },
    bloodType: {
      encrypt: {
        bsonType: "string",
        algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Random",
      },
    },
    ssn: {
      encrypt: {
        bsonType: "int",
        algorithm: "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
      },
    },
  },
};
var patientSchema = {};
patientSchema[namespace] = schema;
dek_id = b"<paste-base-64-encoded-data-encryption-key-id>"
json_schema = {
    "bsonType": "object",
    "encryptMetadata": {"keyId": [Binary(base64.b64decode(dek_id), UUID_SUBTYPE)]},
    "properties": {
        "insurance": {
            "bsonType": "object",
            "properties": {
                "policyNumber": {
                    "encrypt": {
                        "bsonType": "int",
                        "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
                    }
                }
            },
        },
        "medicalRecords": {
            "encrypt": {
                "bsonType": "array",
                "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random",
            }
        },
        "bloodType": {
            "encrypt": {
                "bsonType": "string",
                "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random",
            }
        },
        "ssn": {
            "encrypt": {
                "bsonType": "int",
                "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
            }
        },
    },
}
patient_schema = {"medicalRecords.patients": json_schema}
4

Specify the Location of the Automatic Encryption Shared Library

var mongoBinariesPath = "<Full path to your Automatic Encryption Shared Library>";
var extraOptions = new Dictionary<string, object>()
{
   { "cryptSharedLibPath", mongoBinariesPath },
};
extraOptions := map[string]interface{}{
	"cryptSharedLibPath": "<Full path to your Automatic Encryption Shared Library>",
}
Map<String, Object> extraOptions = new HashMap<String, Object>();
extraOptions.put("cryptSharedLibPath", "<Full path to your Automatic Encryption Shared Library>"));
const extraOptions = {
  cryptSharedLibPath: "<Full path to your Automatic Encryption Shared Library>",
};
extra_options = {
    "cryptSharedLibPath": "<Full path to your Automatic Encryption Shared Library>"
}

Note

Automatic Encryption Options

The automatic encryption options provide configuration information to the Automatic Encryption Shared Library, which modifies the application's behavior when accessing encrypted fields.

To learn more about the Automatic Encryption Shared Library, see the Automatic Encryption Shared Library for CSFLE page.

5

Create the MongoClient

Instantiate a MongoDB client object with the following automatic encryption settings:

var clientSettings = MongoClientSettings.FromConnectionString(connectionString);
var autoEncryptionOptions = new AutoEncryptionOptions(
    keyVaultNamespace: keyVaultNamespace,
    kmsProviders: kmsProviders,
    schemaMap: schemaMap,
    extraOptions: extraOptions
    );
clientSettings.AutoEncryptionOptions = autoEncryptionOptions;
var secureClient = new MongoClient(clientSettings);
autoEncryptionOpts := options.AutoEncryption().
	SetKmsProviders(kmsProviders).
	SetKeyVaultNamespace(keyVaultNamespace).
	SetSchemaMap(schemaMap).
	SetExtraOptions(extraOptions)
secureClient, 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() {
	_ = secureClient.Disconnect(context.TODO())
}()
MongoClientSettings clientSettings = MongoClientSettings.builder()
    .applyConnectionString(new ConnectionString(connectionString))
    .autoEncryptionSettings(AutoEncryptionSettings.builder()
        .keyVaultNamespace(keyVaultNamespace)
        .kmsProviders(kmsProviders)
        .schemaMap(schemaMap)
        .extraOptions(extraOptions)
        .build())
    .build();
MongoClient mongoClientSecure = MongoClients.create(clientSettings);
const secureClient = new MongoClient(connectionString, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  autoEncryption: {
    keyVaultNamespace,
    kmsProviders,
    schemaMap: patientSchema,
    extraOptions: extraOptions,
  },
});
fle_opts = AutoEncryptionOpts(
    kms_providers, key_vault_namespace, schema_map=patient_schema, **extra_options
)
secureClient = MongoClient(connection_string, auto_encryption_opts=fle_opts)
5

Insert a Document with Encrypted Fields

Use your CSFLE-enabled MongoClient instance to insert a document with encrypted fields into the medicalRecords.patients namespace using the following code snippet:

var sampleDocFields = new BsonDocument
{
    { "name", "Jon Doe" },
    { "ssn", 145014000 },
    { "bloodType", "AB-" },
    {
        "medicalRecords", new BsonArray
        {
            new BsonDocument("weight", 180),
            new BsonDocument("bloodPressure", "120/80")
        }
    },
    {
        "insurance", new BsonDocument
        {
            { "policyNumber", 123142 },
            { "provider", "MaestCare" }
        }
    }
};
// Construct an auto-encrypting client
var secureCollection = secureClient.GetDatabase(db).GetCollection<BsonDocument>(coll);
// Insert a document into the collection
secureCollection.InsertOne(sampleDocFields);
test_patient := map[string]interface{}{
	"name":      "Jon Doe",
	"ssn":       241014209,
	"bloodType": "AB+",
	"medicalRecords": []map[string]interface{}{{
		"weight":        180,
		"bloodPressure": "120/80",
	}},
	"insurance": map[string]interface{}{
		"provider":     "MaestCare",
		"policyNumber": 123142,
	},
}
if _, err := secureClient.Database(dbName).Collection(collName).InsertOne(context.TODO(), test_patient); err != nil {
	return fmt.Errorf("InsertOne error: %v", err)
}

Note

Rather than creating a raw BSON document, you can pass a struct with bson tags directly to the driver for encoding.

ArrayList<Document> medicalRecords = new ArrayList<>();
medicalRecords.add(new Document().append("weight", "180"));
medicalRecords.add(new Document().append("bloodPressure", "120/80"));
Document insurance = new Document()
.append("policyNumber", 123142)
.append("provider",  "MaestCare");
Document patient = new Document()
    .append("name", "Jon Doe")
    .append("ssn", 241014209)
    .append("bloodType", "AB+")
    .append("medicalRecords", medicalRecords)
    .append("insurance", insurance);
mongoClientSecure.getDatabase(recordsDb).getCollection(recordsColl).insertOne(patient);
try {
  const writeResult = await secureClient
    .db(db)
    .collection(coll)
    .insertOne({
      name: "Jon Doe",
      ssn: 241014209,
      bloodType: "AB+",
      medicalRecords: [{ weight: 180, bloodPressure: "120/80" }],
      insurance: {
        policyNumber: 123142,
        provider: "MaestCare",
      },
    });
} catch (writeError) {
  console.error("writeError occurred:", writeError);
}
def insert_patient(
    collection, name, ssn, blood_type, medical_records, policy_number, provider
):
    insurance = {"policyNumber": policy_number, "provider": provider}
    doc = {
        "name": name,
        "ssn": ssn,
        "bloodType": blood_type,
        "medicalRecords": medical_records,
        "insurance": insurance,
    }
    collection.insert_one(doc)
medical_record = [{"weight": 180, "bloodPressure": "120/80"}]
insert_patient(
    secureClient.medicalRecords.patients,
    "Jon Doe",
    241014209,
    "AB+",
    medical_record,
    123142,
    "MaestCare",
)

When you insert a document, your CSFLE-enabled client encrypts the fields of your document such that it resembles the following:

{
  "_id": { "$oid": "<_id of your document>" },
  "name": "Jon Doe",
  "ssn": {
    "$binary": "<cipher-text>",
    "$type": "6"
  },
  "bloodType": {
    "$binary": "<cipher-text>",
    "$type": "6"
  },
  "medicalRecords": {
    "$binary": "<cipher-text>",
    "$type": "6"
  },
  "insurance": {
    "provider": "MaestCare",
    "policyNumber": {
      "$binary": "<cipher-text>",
      "$type": "6"
    }
  }
}

Tip

See: Complete Code

To view the complete code for inserting a document with encrypted fields, see our Github repository

To view the complete code for inserting a document with encrypted fields, see our Github repository.

To view the complete code for inserting a document with encrypted fields, see our Github repository.

To view the complete code for inserting a document with encrypted fields, see our Github repository.

To view the complete code for inserting a document with encrypted fields, see our Github repository.

6

Retrieve Your Document with Encrypted Fields

Retrieve the document with encrypted fields you inserted in the Insert a Document with Encrypted Fields step of this guide.

To show the functionality of CSFLE, the following code snippet queries for your document with a client configured for automatic CSFLE as well as a client that is not configured for automatic CSFLE.

Console.WriteLine("Finding a document with regular (non-encrypted) client.");
var filter = Builders<BsonDocument>.Filter.Eq("name", "Jon Doe");
var regularResult = regularCollection.Find(filter).Limit(1).ToList()[0];
Console.WriteLine($"\n{regularResult}\n");
Console.WriteLine("Finding a document with encrypted client, searching on an encrypted field");
var ssnFilter = Builders<BsonDocument>.Filter.Eq("ssn", 145014000);
var secureResult = secureCollection.Find(ssnFilter).Limit(1).First();
Console.WriteLine($"\n{secureResult}\n");
fmt.Println("Finding a document with regular (non-encrypted) client.")
var resultRegular bson.M
err = regularClient.Database(dbName).Collection(collName).FindOne(context.TODO(), bson.D{{"name", "Jon Doe"}}).Decode(&resultRegular)
if err != nil {
	panic(err)
}
outputRegular, err := json.MarshalIndent(resultRegular, "", "    ")
if err != nil {
	panic(err)
}
fmt.Printf("%s\n", outputRegular)
fmt.Println("Finding a document with encrypted client, searching on an encrypted field")
var resultSecure bson.M
err = secureClient.Database(dbName).Collection(collName).FindOne(context.TODO(), bson.D{{"ssn", "241014209"}}).Decode(&resultSecure)
if err != nil {
	panic(err)
}
outputSecure, err := json.MarshalIndent(resultSecure, "", "    ")
if err != nil {
	panic(err)
}
fmt.Printf("%s\n", outputSecure)
System.out.println("Finding a document with regular (non-encrypted) client.");
Document docRegular = mongoClientRegular.getDatabase(recordsDb).getCollection(recordsColl).find(eq("name", "Jon Doe")).first();
System.out.println(docRegular.toJson());
System.out.println("Finding a document with encrypted client, searching on an encrypted field");
Document docSecure = mongoClientSecure.getDatabase(recordsDb).getCollection(recordsColl).find(eq("ssn", 241014209)).first();
System.out.println(docSecure.toJson());
console.log("Finding a document with regular (non-encrypted) client.");
console.log(
  await regularClient.db(db).collection(coll).findOne({ name: /Jon/ })
);
console.log(
  "Finding a document with encrypted client, searching on an encrypted field"
);
console.log(
  await secureClient.db(db).collection(coll).findOne({ ssn: "241014209" })
);
print("Finding a document with regular (non-encrypted) client.")
result = regularClient.medicalRecords.patients.find_one({"name": "Jon Doe"})
pprint.pprint(result)
print("Finding a document with encrypted client, searching on an encrypted field")
pprint.pprint(secureClient.medicalRecords.patients.find_one({"ssn": 241014209}))

The output of the preceding code snippet should look like this:

Finding a document with regular (non-encrypted) client.
{
  _id: new ObjectId("629a452e0861b3130887103a"),
  name: 'Jon Doe',
  ssn: new Binary(Buffer.from("0217482732d8014cdd9ffdd6e2966e5e7910c20697e5f4fa95710aafc9153f0a3dc769c8a132a604b468732ff1f4d8349ded3244b59cbfb41444a210f28b21ea1b6c737508d9d30e8baa30c1d8070c4d5e26", "hex"), 6),
  bloodType: new Binary(Buffer.from("0217482732d8014cdd9ffdd6e2966e5e79022e238536dfd8caadb4d7751ac940e0f195addd7e5c67b61022d02faa90283ab69e02303c7e4001d1996128428bf037dea8bbf59fbb20c583cbcff2bf3e2519b4", "hex"), 6),
  'key-id': 'demo-data-key',
  medicalRecords: new Binary(Buffer.from("0217482732d8014cdd9ffdd6e2966e5e790405163a3207cff175455106f57eef14e5610c49a99bcbd14a7db9c5284e45e3ee30c149354015f941440bf54725d6492fb3b8704bc7c411cff6c868e4e13c58233c3d5ed9593eca4e4d027d76d3705b6d1f3b3c9e2ceee195fd944b553eb27eee69e5e67c338f146f8445995664980bf0", "hex"), 6),
  insurance: {
    policyNumber: new Binary(Buffer.from("0217482732d8014cdd9ffdd6e2966e5e79108decd85c05be3fec099e015f9d26d9234605dc959cc1a19b63072f7ffda99db38c7b487de0572a03b2139ac3ee163bcc40c8508f366ce92a5dd36e38b3c742f7", "hex"), 6),
    provider: 'MaestCare'
  }
}
Finding a document with encrypted client, searching on an encrypted field
{
  _id: new ObjectId("629a452e0861b3130887103a"),
  name: 'Jon Doe',
  ssn: 241014209,
  bloodType: 'AB+',
  'key-id': 'demo-data-key',
  medicalRecords: [ { weight: 180, bloodPressure: '120/80' } ],
  insurance: { policyNumber: 123142, provider: 'MaestCare' }
}

Tip

See: Complete Code

To view the complete code for finding a document with encrypted fields, see our Github repository

To view the complete code for finding a document with encrypted fields, see our Github repository.

To view the complete code for finding a document with encrypted fields, see our Github repository.

To view the complete code for finding a document with encrypted fields, see our Github repository.

To view the complete code for finding a document with encrypted fields, see our Github repository.

Learn More

To view a tutorial on production-ready CSFLE with a remote KMS, see Tutorials.

To learn how CSFLE works, see Fundamentals.

To learn more about the topics mentioned in this guide, see the following links:

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