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Use Automatic Client-Side Field Level Encryption with GCP

This guide shows you how to build a Client-Side Field Level Encryption (CSFLE)-enabled application using Google Cloud Key Management Service.

After you complete the steps in this guide, you should have:

  • A CMK hosted on Google Cloud Key Management Service.

  • A client application that inserts documents with encrypted fields using your CMK.

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

Throughout this guide, code examples use placeholder text. Before you run the examples, substitute your own values for these placeholders.

For example:

dek_id := "<Your Base64 DEK ID>"

You would replace everything between quotes with your DEK ID.

dek_id := "abc123"

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:

// You are viewing the .NET/C# driver code examples.// Use the dropdown menu to select a different driver.
1

To create a service account on Google Cloud, follow the Creating a service account guide in Google's official documentation.

To add a service account key on Google Cloud, follow the Managing service account keys guide in Google's official documentation.

Important

When creating your service account key, you receive a one-time download of the private key information. Make sure to download this file in either the PKCS12 or JSON format for use later in this tutorial.

2

Create a key ring and a symmetric key by following the Create a key guide from Google's official documentation.

This key is your Customer Master Key (CMK).

Record the following details of your CMK for use in a future step of this tutorial.

Field
Required
Description

key_name

Yes

Identifier for the CMK.

key_ring

Yes

Identifier for the group of keys your key belongs to.

key_version

No

The version of the named key.

location

Yes

Region specified for your key.

endpoint

No

The host and optional port of the Google Cloud KMS. The default value is cloudkms.googleapis.com.

Select the tab that corresponds to the MongoDB driver you are using in your application to see relevant code samples.

1

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

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);
2

Unless you're using an attached service account or an access token, add the service account credentials to your CSFLE-enabled client, as shown in the following code example. To learn about all supported credential forms for GCP, see kmsProviders Object.

var kmsProviders = new Dictionary<string, IReadOnlyDictionary<string, object>>();var provider = "gcp";var gcpKmsOptions = new Dictionary<string, object>{ { "privateKey", "<Your GCP Private Key>" }, { "email", "<Your GCP Email>" },};kmsProviders.Add(provider, gcpKmsOptions);

Tip

You saved a file containing your service account key credentials in the Create a GCP Service Account step of this guide.

If you downloaded your credentials in JSON format, you can use the following command to extract the value of your private key, substituting <credentials-filename> with the name of your credentials file. The following command requires that you install OpenSSL:

cat <credentials-filename> | jq -r .private_key | openssl pkcs8 -topk8 -nocrypt -inform PEM -outform DER | base64

If you downloaded your credentials in PKCS12 format, you need to specify your GCP service account import password and to add a PEM pass phrase to access the key when accessing it using the following command, substituting <credentials-filename> with the name of your credentials file:

openssl pkcs12 -info -in <credentials-filename>

Update the following code to specify your Customer Master Key:

Tip

You recorded your Customer Master Key details in the in the Create a Customer Master Key step of this guide.

var dataKeyOptions = new DataKeyOptions( masterKey: new BsonDocument { { "projectId", "Your GCP Project ID" }, { "location", "Your GCP Key Location" } , { "keyRing", "<Your GCP Key Ring>" }, { "keyName", "<Your GCP Key Name>" }, });

Generate your Data Encryption Key using the variables declared in step one of this tutorial.

var clientEncryptionOptions = new ClientEncryptionOptions( keyVaultClient: keyVaultClient, keyVaultNamespace: keyVaultNamespace, kmsProviders: kmsProviders ); var clientEncryption = new ClientEncryption(clientEncryptionOptions);var dataKeyId = clientEncryption.CreateDataKey(provider, dataKeyOptions, CancellationToken.None);var dataKeyIdBase64 = Convert.ToBase64String(GuidConverter.ToBytes(dataKeyId, GuidRepresentation.Standard));Console.WriteLine($"DataKeyId [base64]: {dataKeyIdBase64}");

Tip

Learn More

To view a diagram showing how your client application creates your Data Encryption Key when using an Google Cloud Key Management Service, see Architecture.

To learn more about the options for creating a Data Encryption Key encrypted with a Customer Master Key hosted in Azure Key Vault, see kmsProviders Object and dataKeyOpts Object.

Tip

See: Complete Code

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

3

Tip

Follow the remaining steps in this tutorial in a separate file from the one created in the previous steps.

To view the complete code for this file, see our Github repository

Specify encryption.__keyVault as the Key Vault collection namespace.

var keyVaultNamespace = CollectionNamespace.FromFullName("encryption.__keyVault");

Unless you're using an attached service account or an access token, add the service account credentials to your CSFLE-enabled client, as shown in the following code example. To learn about all supported credential forms for GCP, see kmsProviders Object.

var kmsProviders = new Dictionary<string, IReadOnlyDictionary<string, object>>();var provider = "gcp";var gcpKmsOptions = new Dictionary<string, object>{ { "privateKey", "<Your GCP Private Key>" }, { "email", "<Your GCP Email>" },};kmsProviders.Add(provider, gcpKmsOptions);

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);
var mongoBinariesPath = "<Full path to your Automatic Encryption Shared Library>";var extraOptions = new Dictionary<string, object>(){ { "cryptSharedLibPath", mongoBinariesPath },};

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.

Instantiate a MongoDB client object with the following automatic encryption settings that use the variables declared in the previous steps:

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);
4

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 clientvar secureCollection = secureClient.GetDatabase(db).GetCollection<BsonDocument>(coll); // Insert a document into the collectionsecureCollection.InsertOne(sampleDocFields);

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

5

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");

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