Destroying and restoring key versions

In Cloud KMS, the cryptographic key material that you use to encrypt, decrypt, sign, and verify data is stored in a key version. A key has zero or more key versions. When you rotate a key, you create a new key version.

This topic shows how to schedule a key version for permanent destruction. After a key is destroyed, data that was encrypted with the key cannot be accessed.

When you submit a request to destroy a key version, destruction occurs after 24 hours unless you cancel the destruction request by restoring the key version. You can also manage access to the key using Identity and Access Management (IAM). IAM operations are consistent within seconds. For more information, see Using IAM.

You can also temporarily disable a key version.

In the rest of this topic, scheduling a key for destruction is referred to as destroying the key, even though destruction is not immediate.

Destroy a key version

You can destroy an enabled or disabled key version.

Web UI

  1. Go to the Cryptographic Keys page in the Cloud Console.

    Go to the Cryptographic Keys page

  2. Click the name of the key ring that contains the key whose key version you will schedule for destruction.

  3. Click the key whose key version you want to schedule for destruction.

  4. Check the box next to the key version that you want to schedule for destruction.

  5. Click Destroy in the header.

  6. In the confirmation prompt, enter the key name and then click Schedule Destruction.

Command-line

To use Cloud KMS on the command line, first Install or upgrade to the latest version of Cloud SDK.

gcloud kms keys versions destroy key-version \
    --key key \
    --keyring key-ring \
    --location location

Replace key-version with the version of the key to destroy. Replace key with the name of the key. Replace key-ring with the name of the key ring where the key iis located. Replace location with the Cloud KMS location for the key ring.

For information on all flags and possible values, run the command with the --help flag.

C#

To run this code, first set up a C# development environment and install the Cloud KMS C# SDK.


using Google.Cloud.Kms.V1;

public class DestroyKeyVersionSample
{
    public CryptoKeyVersion DestroyKeyVersion(
      string projectId = "my-project", string locationId = "us-east1", string keyRingId = "my-key-ring", string keyId = "my-key", string keyVersionId = "123")
    {
        // Create the client.
        KeyManagementServiceClient client = KeyManagementServiceClient.Create();

        // Build the key version name.
        CryptoKeyVersionName keyVersionName = new CryptoKeyVersionName(projectId, locationId, keyRingId, keyId, keyVersionId);

        // Call the API.
        CryptoKeyVersion result = client.DestroyCryptoKeyVersion(keyVersionName);

        // Return the result.
        return result;
    }
}

Go

To run this code, first set up a Go development environment and install the Cloud KMS Go SDK.

import (
	"context"
	"fmt"
	"io"

	kms "cloud.google.com/go/kms/apiv1"
	kmspb "google.golang.org/genproto/googleapis/cloud/kms/v1"
)

// destroyKeyVersion marks a specified key version for deletion. The key can be
// restored if requested within 24 hours.
func destroyKeyVersion(w io.Writer, name string) error {
	// parent := "projects/my-project/locations/us-east1/keyRings/my-key-ring/cryptoKeys/my-key/cryptoKeyVersions/123"

	// Create the client.
	ctx := context.Background()
	client, err := kms.NewKeyManagementClient(ctx)
	if err != nil {
		return fmt.Errorf("failed to create kms client: %v", err)
	}

	// Build the request.
	req := &kmspb.DestroyCryptoKeyVersionRequest{
		Name: name,
	}

	// Call the API.
	result, err := client.DestroyCryptoKeyVersion(ctx, req)
	if err != nil {
		return fmt.Errorf("failed to destroy key version: %v", err)
	}
	fmt.Fprintf(w, "Destroyed key version: %s\n", result)
	return nil
}

Java

To run this code, first set up a Java development environment and install the Cloud KMS Java SDK.

import com.google.cloud.kms.v1.CryptoKeyVersion;
import com.google.cloud.kms.v1.CryptoKeyVersionName;
import com.google.cloud.kms.v1.KeyManagementServiceClient;
import java.io.IOException;

public class DestroyKeyVersion {

  public void destroyKeyVersion() throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "your-project-id";
    String locationId = "us-east1";
    String keyRingId = "my-key-ring";
    String keyId = "my-key";
    String keyVersionId = "123";
    destroyKeyVersion(projectId, locationId, keyRingId, keyId, keyVersionId);
  }

  // Schedule destruction of the given key version.
  public void destroyKeyVersion(
      String projectId, String locationId, String keyRingId, String keyId, String keyVersionId)
      throws IOException {
    // Initialize client that will be used to send requests. This client only
    // needs to be created once, and can be reused for multiple requests. After
    // completing all of your requests, call the "close" method on the client to
    // safely clean up any remaining background resources.
    try (KeyManagementServiceClient client = KeyManagementServiceClient.create()) {
      // Build the key version name from the project, location, key ring, key,
      // and key version.
      CryptoKeyVersionName keyVersionName =
          CryptoKeyVersionName.of(projectId, locationId, keyRingId, keyId, keyVersionId);

      // Destroy the key version.
      CryptoKeyVersion response = client.destroyCryptoKeyVersion(keyVersionName);
      System.out.printf("Destroyed key version: %s%n", response.getName());
    }
  }
}

Node.js

To run this code, first set up a Node.js development environment and install the Cloud KMS Node.js SDK.

//
// TODO(developer): Uncomment these variables before running the sample.
//
// const projectId = 'my-project';
// const locationId = 'us-east1';
// const keyRingId = 'my-key-ring';
// const keyId = 'my-key';
// const versionId = '123';

// Imports the Cloud KMS library
const {KeyManagementServiceClient} = require('@google-cloud/kms');

// Instantiates a client
const client = new KeyManagementServiceClient();

// Build the key version name
const versionName = client.cryptoKeyVersionPath(
  projectId,
  locationId,
  keyRingId,
  keyId,
  versionId
);

async function destroyKeyVersion() {
  const [version] = await client.destroyCryptoKeyVersion({
    name: versionName,
  });

  console.log(`Destroyed key version: ${version.name}`);
  return version;
}

return destroyKeyVersion();

PHP

To run this code, first learn about using PHP on Google Cloud and install the Cloud KMS PHP SDK.

use Google\Cloud\Kms\V1\KeyManagementServiceClient;

function destroy_key_version_sample(
    string $projectId = 'my-project',
    string $locationId = 'us-east1',
    string $keyRingId = 'my-key-ring',
    string $keyId = 'my-key',
    string $versionId = '123'
) {
    // Create the Cloud KMS client.
    $client = new KeyManagementServiceClient();

    // Build the key version name.
    $keyVersionName = $client->cryptoKeyVersionName($projectId, $locationId, $keyRingId, $keyId, $versionId);

    // Call the API.
    $destroyedVersion = $client->destroyCryptoKeyVersion($keyVersionName);
    printf('Destroyed key version: %s' . PHP_EOL, $destroyedVersion->getName());
    return $destroyedVersion;
}

Python

To run this code, first set up a Python development environment and install the Cloud KMS Python SDK.

def destroy_key_version(project_id, location_id, key_ring_id, key_id, version_id):
    """
    Schedule destruction of the given key version.

    Args:
        project_id (string): Google Cloud project ID (e.g. 'my-project').
        location_id (string): Cloud KMS location (e.g. 'us-east1').
        key_ring_id (string): ID of the Cloud KMS key ring (e.g. 'my-key-ring').
        key_id (string): ID of the key to use (e.g. 'my-key').
        version_id (string): ID of the key version to destroy (e.g. '1').

    Returns:
        CryptoKeyVersion: The version.

    """

    # Import the client library.
    from google.cloud import kms

    # Create the client.
    client = kms.KeyManagementServiceClient()

    # Build the key version name.
    key_version_name = client.crypto_key_version_path(project_id, location_id, key_ring_id, key_id, version_id)

    # Call the API.
    destroyed_version = client.destroy_crypto_key_version(request={'name': key_version_name})
    print('Destroyed key version: {}'.format(destroyed_version.name))
    return destroyed_version

Ruby

To run this code, first set up a Ruby development environment and install the Cloud KMS Ruby SDK.

# TODO(developer): uncomment these values before running the sample.
# project_id  = "my-project"
# location_id = "us-east1"
# key_ring_id = "my-key-ring"
# key_id      = "my-key"
# version_id  = "123"

# Require the library.
require "google/cloud/kms"

# Create the client.
client = Google::Cloud::Kms.key_management_service

# Build the key version name.
key_version_name = client.crypto_key_version_path project:            project_id,
                                                  location:           location_id,
                                                  key_ring:           key_ring_id,
                                                  crypto_key:         key_id,
                                                  crypto_key_version: version_id

# Call the API.
destroyed_version = client.destroy_crypto_key_version name: key_version_name
puts "Destroyed key version: #{destroyed_version.name}"

When you submit the destruction request, the key version's state becomes Scheduled for destruction. After 24 hours have elapsed, the key version's state becomes Destroyed.

To receive an alert when a key version is scheduled for destruction, see Using Cloud Monitoring with Cloud KMS.

Destroyed key versions are not billed resources.

Restore a key version

During the period when a key version's status is Scheduled for destruction, you can restore the key version by submitting a restoration request.

Web UI

  1. Go to the Cryptographic Keys page in the Cloud Console.

    Go to the Cryptographic Keys page

  2. Click the name of the key ring that contains the key whose key version you will restore.

  3. Click the key whose key version you want to restore.

  4. Check the box next to the key version that you want to restore.

  5. Click Restore in the header.

  6. In the confirmation prompt, click Restore.

Command-line

To use Cloud KMS on the command line, first Install or upgrade to the latest version of Cloud SDK.

gcloud kms keys versions restore key-version \
    --key key \
    --keyring key-ring \
    --location location

Replace key-version with the version of the key to restore. Replace key with the name of the key. Replace key-ring with the name of the key ring where the key is located. Replace location with the Cloud KMS location for the key ring.

For information on all flags and possible values, run the command with the --help flag.

C#

To run this code, first set up a C# development environment and install the Cloud KMS C# SDK.


using Google.Cloud.Kms.V1;

public class RestoreKeyVersionSample
{
    public CryptoKeyVersion RestoreKeyVersion(string projectId = "my-project", string locationId = "us-east1", string keyRingId = "my-key-ring", string keyId = "my-key", string keyVersionId = "123")
    {
        // Create the client.
        KeyManagementServiceClient client = KeyManagementServiceClient.Create();

        // Build the key version name.
        CryptoKeyVersionName cryptoKeyVersionName = new CryptoKeyVersionName(projectId, locationId, keyRingId, keyId, keyVersionId);

        // Call the API.
        CryptoKeyVersion result = client.RestoreCryptoKeyVersion(cryptoKeyVersionName);

        // Return the result.
        return result;
    }
}

Go

To run this code, first set up a Go development environment and install the Cloud KMS Go SDK.

import (
	"context"
	"fmt"
	"io"

	kms "cloud.google.com/go/kms/apiv1"
	kmspb "google.golang.org/genproto/googleapis/cloud/kms/v1"
)

// restoreKeyVersion attempts to recover a key that has been marked for
// destruction in the past 24h.
func restoreKeyVersion(w io.Writer, name string) error {
	// name := "projects/my-project/locations/us-east1/keyRings/my-key-ring/cryptoKeys/my-key/cryptoKeyVersions/123"

	// Create the client.
	ctx := context.Background()
	client, err := kms.NewKeyManagementClient(ctx)
	if err != nil {
		return fmt.Errorf("failed to create kms client: %v", err)
	}

	// Build the request.
	req := &kmspb.RestoreCryptoKeyVersionRequest{
		Name: name,
	}

	// Call the API.
	result, err := client.RestoreCryptoKeyVersion(ctx, req)
	if err != nil {
		return fmt.Errorf("failed to restore key version: %v", err)
	}
	fmt.Fprintf(w, "Restored key version: %s\n", result)
	return nil
}

Java

To run this code, first set up a Java development environment and install the Cloud KMS Java SDK.

import com.google.cloud.kms.v1.CryptoKeyVersion;
import com.google.cloud.kms.v1.CryptoKeyVersionName;
import com.google.cloud.kms.v1.KeyManagementServiceClient;
import java.io.IOException;

public class RestoreKeyVersion {

  public void restoreKeyVersion() throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "your-project-id";
    String locationId = "us-east1";
    String keyRingId = "my-key-ring";
    String keyId = "my-key";
    String keyVersionId = "123";
    restoreKeyVersion(projectId, locationId, keyRingId, keyId, keyVersionId);
  }

  // Schedule destruction of the given key version.
  public void restoreKeyVersion(
      String projectId, String locationId, String keyRingId, String keyId, String keyVersionId)
      throws IOException {
    // Initialize client that will be used to send requests. This client only
    // needs to be created once, and can be reused for multiple requests. After
    // completing all of your requests, call the "close" method on the client to
    // safely clean up any remaining background resources.
    try (KeyManagementServiceClient client = KeyManagementServiceClient.create()) {
      // Build the key version name from the project, location, key ring, key,
      // and key version.
      CryptoKeyVersionName keyVersionName =
          CryptoKeyVersionName.of(projectId, locationId, keyRingId, keyId, keyVersionId);

      // Restore the key version.
      CryptoKeyVersion response = client.restoreCryptoKeyVersion(keyVersionName);
      System.out.printf("Restored key version: %s%n", response.getName());
    }
  }
}

Node.js

To run this code, first set up a Node.js development environment and install the Cloud KMS Node.js SDK.

//
// TODO(developer): Uncomment these variables before running the sample.
//
// const projectId = 'my-project';
// const locationId = 'us-east1';
// const keyRingId = 'my-key-ring';
// const keyId = 'my-key';
// const versionId = '123';

// Imports the Cloud KMS library
const {KeyManagementServiceClient} = require('@google-cloud/kms');

// Instantiates a client
const client = new KeyManagementServiceClient();

// Build the key version name
const versionName = client.cryptoKeyVersionPath(
  projectId,
  locationId,
  keyRingId,
  keyId,
  versionId
);

async function restoreKeyVersion() {
  const [version] = await client.restoreCryptoKeyVersion({
    name: versionName,
  });

  console.log(`Restored key version: ${version.name}`);
  return version;
}

return restoreKeyVersion();

PHP

To run this code, first learn about using PHP on Google Cloud and install the Cloud KMS PHP SDK.

use Google\Cloud\Kms\V1\KeyManagementServiceClient;

function restore_key_version_sample(
    string $projectId = 'my-project',
    string $locationId = 'us-east1',
    string $keyRingId = 'my-key-ring',
    string $keyId = 'my-key',
    string $versionId = '123'
) {
    // Create the Cloud KMS client.
    $client = new KeyManagementServiceClient();

    // Build the key version name.
    $keyVersionName = $client->cryptoKeyVersionName($projectId, $locationId, $keyRingId, $keyId, $versionId);

    // Call the API.
    $restoredVersion = $client->restoreCryptoKeyVersion($keyVersionName);
    printf('Restored key version: %s' . PHP_EOL, $restoredVersion->getName());
    return $restoredVersion;
}

Python

To run this code, first set up a Python development environment and install the Cloud KMS Python SDK.

def restore_key_version(project_id, location_id, key_ring_id, key_id, version_id):
    """
    Restore a key version scheduled for destruction.

    Args:
        project_id (string): Google Cloud project ID (e.g. 'my-project').
        location_id (string): Cloud KMS location (e.g. 'us-east1').
        key_ring_id (string): ID of the Cloud KMS key ring (e.g. 'my-key-ring').
        key_id (string): ID of the key to use (e.g. 'my-key').
        version_id (string): ID of the version to use (e.g. '1').

    Returns:
        CryptoKeyVersion: Restored Cloud KMS key version.

    """

    # Import the client library.
    from google.cloud import kms

    # Create the client.
    client = kms.KeyManagementServiceClient()

    # Build the key version name.
    key_version_name = client.crypto_key_version_path(project_id, location_id, key_ring_id, key_id, version_id)

    # Call the API.
    restored_version = client.restore_crypto_key_version(request={'name': key_version_name})
    print('Restored key version: {}'.format(restored_version.name))
    return restored_version

Ruby

To run this code, first set up a Ruby development environment and install the Cloud KMS Ruby SDK.

# TODO(developer): uncomment these values before running the sample.
# project_id  = "my-project"
# location_id = "us-east1"
# key_ring_id = "my-key-ring"
# key_id      = "my-key"
# version_id  = "123"

# Require the library.
require "google/cloud/kms"

# Create the client.
client = Google::Cloud::Kms.key_management_service

# Build the key version name.
key_version_name = client.crypto_key_version_path project:            project_id,
                                                  location:           location_id,
                                                  key_ring:           key_ring_id,
                                                  crypto_key:         key_id,
                                                  crypto_key_version: version_id

# Call the API.
restored_version = client.restore_crypto_key_version name: key_version_name
puts "Restored key version: #{restored_version.name}"

After the restoration request completes, the key version's state becomes Disabled. You must enable the key before it can be used.

Required IAM permissions

To destroy a key version, the caller needs the cloudkms.cryptoKeyVersions.destroy IAM permission on the key, the key ring, or the project, folder, or organization.

To restore a key version, the caller needs the cloudkms.cryptoKeyVersions.restore permission.

Both of these permissions are granted to the Cloud KMS Admin role (roles/cloudkms.admin).