Hash-based Message Authentication Code (HMAC) keys let service accounts
authenticate requests to the Cloud Storage XML API. For example, you can use
HMAC keys when you want to move data between other cloud storage providers and
Cloud Storage. This document shows you how to create, disable, and
delete the HMAC keys that are associated with service accounts in your project.

For background information about HMAC keys, see [HMAC keys](https://docs.cloud.google.com/storage/docs/authentication/hmackeys.md.txt).

## Before you begin

Before using this feature in Cloud Storage, you must meet the following
requirements:

1. Have sufficient permission to work with HMAC keys in the selected project:

   - If you own the project, you most likely have the necessary permissions.

   - You should have the Identity and Access Management (IAM) permissions that are prefixed with
     `storage.hmacKeys` for the project. See [Using IAM Permissions](https://docs.cloud.google.com/storage/docs/access-control/using-iam-permissions.md.txt) for
     instructions on how to get a role, such as **Storage HMAC Key Admin**,
     that has these permissions.

2. Have a service account in your project that you intend to create HMAC keys
   for. See [Creating a service account](https://docs.cloud.google.com/iam/docs/creating-managing-service-accounts#creating_a_service_account) if you don't already have one.

3. Make sure the following organization policy constraints are disabled:

   - [`constraints/storage.restrictAuthTypes`](https://docs.cloud.google.com/storage/docs/org-policy-constraints.md.txt#restrict-auth-types) (must be disabled for HMAC
     key authentication)

   - [`constraints/iam.disableServiceAccountKeyCreation`](https://docs.cloud.google.com/resource-manager/docs/organization-policy/restricting-service-accounts#disable_service_account_key_creation)

   See [Creating and managing organization policies](https://docs.cloud.google.com/resource-manager/docs/organization-policy/creating-managing-policies) for instructions on how
   to check and disable constraints.

## Create an HMAC key

> [!IMPORTANT]
> **Important:** When you create an HMAC key, you are given the *secret* for that key, which you must store securely. If you lose the secret, you are no longer able to use the HMAC key to authorize requests.

To create an HMAC key for a service account:

### Console

1. In the Google Cloud console, go to the Cloud Storage **Settings** page.  

   [Go to Settings](https://console.cloud.google.com/storage/settings)
2. Select the **Interoperability** tab.

3. Click
   **Create a key for a service account**.

4. Select the service account you want the HMAC key to be associated with.

5. Click **Create key**.

To learn how to get detailed error information about failed Cloud Storage
operations in the Google Cloud console, see
[Troubleshooting](https://docs.cloud.google.com/storage/docs/troubleshooting.md.txt#trouble-console).

### Command line

Use the [`hmac create`](https://docs.cloud.google.com/sdk/gcloud/reference/storage/hmac/create) command:

```
gcloud storage hmac create SERVICE_ACCOUNT_EMAIL
```

Where `SERVICE_ACCOUNT_EMAIL` is the email address
associated with your service account. For example,
`example-service-account@my-pet-project.iam.gserviceaccount.com`.

If successful, the response contains an [HMAC key resource](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys.md.txt#resource-representations),
including values for the `accessId` and `secret`.

### Client libraries


### C++


For more information, see the
[Cloud Storage C++ API
reference documentation](https://docs.cloud.google.com/cpp/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```c++
namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
return [](gcs::Client client, std::string const& service_account_email) {
  StatusOr<std::pair<gcs::HmacKeyMetadata, std::string>> key_info =
      client.CreateHmacKey(service_account_email);
  if (!key_info) throw std::move(key_info).status();

  std::cout << "The base64 encoded secret is: " << key_info->second
            << "\nDo not miss that secret, there is no API to recover it."
            << "\nThe HMAC key metadata is: " << key_info->first << "\n";
  return key_info->first.access_id();
}
```

### C#


For more information, see the
[Cloud Storage C# API
reference documentation](https://cloud.google.com/dotnet/docs/reference/Google.Cloud.Storage.V1/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```c#

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;

public class CreateHmacKeySample
{
    public HmacKey CreateHmacKey(
        string projectId = "your-project-id",
        string serviceAccountEmail = "dev@iam.gserviceaccount.com")
    {
        var storage = StorageClient.Create();
        var key = storage.CreateHmacKey(projectId, serviceAccountEmail);

        var secret = key.Secret;
        var metadata = key.Metadata;

        Console.WriteLine($"The Base64 encoded secret is: {secret}");
        Console.WriteLine("Make sure to save that secret, there's no API to recover it.");
        Console.WriteLine("The HMAC key metadata is:");
        Console.WriteLine($"ID: {metadata.Id}");
        Console.WriteLine($"Access ID: {metadata.AccessId}");
        Console.WriteLine($"Project ID: {metadata.ProjectId}");
        Console.WriteLine($"Service Account Email: {metadata.ServiceAccountEmail}");
        Console.WriteLine($"State: {metadata.State}");
        Console.WriteLine($"Time Created: {metadata.TimeCreated}");
        Console.WriteLine($"Time Updated: {metadata.Updated}");
        Console.WriteLine($"ETag: {metadata.ETag}");
        return key;
    }
}
```

### Go


For more information, see the
[Cloud Storage Go API
reference documentation](https://pkg.go.dev/cloud.google.com/go/storage).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// createHMACKey creates a new HMAC key using the given project and service account.
func createHMACKey(w io.Writer, projectID string, serviceAccountEmail string) (*storage.HMACKey, error) {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	key, err := client.CreateHMACKey(ctx, projectID, serviceAccountEmail)
	if err != nil {
		return nil, fmt.Errorf("CreateHMACKey: %w", err)
	}

	fmt.Fprintf(w, "%s\n", key)
	fmt.Fprintf(w, "The base64 encoded secret is %s\n", key.Secret)
	fmt.Fprintln(w, "Do not miss that secret, there is no API to recover it.")
	fmt.Fprintln(w, "The HMAC key metadata is")
	fmt.Fprintf(w, "%+v", key)

	return key, nil
}
```

### Java


For more information, see the
[Cloud Storage Java API
reference documentation](https://cloud.google.com/java/docs/reference/google-cloud-storage/latest/overview).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```java

import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.ServiceAccount;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.util.Date;

public class CreateHmacKey {
  public static void createHmacKey(String serviceAccountEmail, String projectId)
      throws StorageException {

    // The service account email for which the new HMAC key will be created.
    // String serviceAccountEmail = "service-account@iam.gserviceaccount.com";

    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    ServiceAccount account = ServiceAccount.of(serviceAccountEmail);
    HmacKey hmacKey =
        storage.createHmacKey(account, Storage.CreateHmacKeyOption.projectId(projectId));

    String secret = hmacKey.getSecretKey();
    HmacKey.HmacKeyMetadata metadata = hmacKey.getMetadata();

    System.out.println("The Base64 encoded secret is: " + secret);
    System.out.println("Do not lose that secret, there is no API to recover it.");
    System.out.println("The HMAC key metadata is:");
    System.out.println("ID: " + metadata.getId());
    System.out.println("Access ID: " + metadata.getAccessId());
    System.out.println("Project ID: " + metadata.getProjectId());
    System.out.println("Service Account Email: " + metadata.getServiceAccount().getEmail());
    System.out.println("State: " + metadata.getState().toString());
    System.out.println("Time Created: " + new Date(metadata.getCreateTime()).toString());
    System.out.println("Time Updated: " + new Date(metadata.getUpdateTime()).toString());
    System.out.println("ETag: " + metadata.getEtag());
  }
}
```

### Node.js


For more information, see the
[Cloud Storage Node.js API
reference documentation](https://cloud.google.com/nodejs/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The service account email for which the new HMAC key will be created
// const serviceAccountEmail = 'service-account@iam.gserviceaccount.com';

// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Create HMAC SA Key
async function createHmacKey() {
  const [hmacKey, secret] = await storage.createHmacKey(serviceAccountEmail, {
    projectId,
  });

  console.log(`The base64 encoded secret is: ${secret}`);
  console.log('Do not miss that secret, there is no API to recover it.');
  console.log('The HMAC key metadata is:');
  for (const [key, value] of Object.entries(hmacKey.metadata)) {
    console.log(`${key}: ${value}`);
  }
}
```

### PHP


For more information, see the
[Cloud Storage PHP API
reference documentation](https://googleapis.github.io/google-cloud-php/#/docs/google-cloud/latest/storage/storageclient).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```php
use Google\Cloud\Storage\StorageClient;

/**
 * Create a new HMAC key.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 * @param string $serviceAccountEmail Service account email to associate with the new HMAC key.
 *        (e.g. 'service-account@iam.gserviceaccount.com')
 */
function create_hmac_key(string $projectId, string $serviceAccountEmail): void
{
    $storage = new StorageClient();
    // By default createHmacKey will use the projectId used by StorageClient().
    $hmacKeyCreated = $storage->createHmacKey($serviceAccountEmail, ['projectId' => $projectId]);

    printf('The base64 encoded secret is: %s' . PHP_EOL, $hmacKeyCreated->secret());
    print('Do not miss that secret, there is no API to recover it.' . PHP_EOL);
    printf('HMAC key Metadata: %s' . PHP_EOL, print_r($hmacKeyCreated->hmacKey()->info(), true));
}
```

### Python


For more information, see the
[Cloud Storage Python API
reference documentation](https://cloud.google.com/python/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```python
from google.cloud import storage


def create_key(project_id, service_account_email):
    """
    Create a new HMAC key using the given project and service account.
    """
    # project_id = 'Your Google Cloud project ID'
    # service_account_email = 'Service account used to generate the HMAC key'

    storage_client = storage.Client(project=project_id)

    hmac_key, secret = storage_client.create_hmac_key(
        service_account_email=service_account_email, project_id=project_id
    )

    print(f"The base64 encoded secret is {secret}")
    print("Do not miss that secret, there is no API to recover it.")
    print("The HMAC key metadata is:")
    print(f"Service Account Email: {hmac_key.service_account_email}")
    print(f"Key ID: {hmac_key.id}")
    print(f"Access ID: {hmac_key.access_id}")
    print(f"Project ID: {hmac_key.project}")
    print(f"State: {hmac_key.state}")
    print(f"Created At: {hmac_key.time_created}")
    print(f"Updated At: {hmac_key.updated}")
    print(f"Etag: {hmac_key.etag}")
    return hmac_key

```

### Ruby


For more information, see the
[Cloud Storage Ruby API
reference documentation](https://googleapis.dev/ruby/google-cloud-storage/latest/Google/Cloud/Storage.html).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```ruby
def create_hmac_key service_account_email:
  # The service account email used to generate an HMAC key
  # service_account_email = "service-my-project-number@gs-project-accounts.iam.gserviceaccount.com"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#create_hmac_key uses the Storage client project_id
  hmac_key = storage.create_hmac_key service_account_email

  puts "The base64 encoded secret is: #{hmac_key.secret}"
  puts "Do not miss that secret, there is no API to recover it."
  puts "\nThe HMAC key metadata is:"
  puts "Key ID:                #{hmac_key.id}"
  puts "Service Account Email: #{hmac_key.service_account_email}"
  puts "Access ID:             #{hmac_key.access_id}"
  puts "Project ID:            #{hmac_key.project_id}"
  puts "Active:                #{hmac_key.active?}"
  puts "Created At:            #{hmac_key.created_at}"
  puts "Updated At:            #{hmac_key.updated_at}"
  puts "Etag:                  #{hmac_key.etag}"
end
```

<br />

### Terraform

You can use a [Terraform resource to create an HMAC key](https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/storage_hmac_key). This sample
also includes a [resource to create a service account](https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/google_service_account).

```terraform
# Create a new service account
resource "google_service_account" "service_account" {
  account_id = "my-svc-acc"
}

# Create the HMAC key for the associated service account
resource "google_storage_hmac_key" "key" {
  service_account_email = google_service_account.service_account.email
}
```

### REST APIs

### JSON API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the JSON API with a [`POST` hmacKeys](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys/create.md.txt)
   request:

   ```
   curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     "https://storage.googleapis.com/storage/v1/projects/PROJECT_IDENTIFIER/hmacKeys?serviceAccountEmail=SERVICE_ACCOUNT_EMAIL"
   ```

   Where:
   - `PROJECT_IDENTIFIER` is the ID or number for the project associated with the key you want to create. For example, `my-pet-project`.
   - `SERVICE_ACCOUNT_EMAIL` is the email address associated with your service account. For example, `example-service-account@my-pet-project.iam.gserviceaccount.com`.

### XML API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the XML API with a [`POST` HMAC Key](https://docs.cloud.google.com/storage/docs/xml-api/post-hmac-create.md.txt)
   request:

   ```
   curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     "https://storage.googleapis.com/?Action=CreateAccessKey&UserName=SERVICE_ACCOUNT_EMAIL"
   ```

   Where `SERVICE_ACCOUNT_EMAIL` is the email
   address associated with your service account. For example,
   `example-service-account@my-pet-project.iam.gserviceaccount.com`.

> [!NOTE]
> **Note:** After creation, it can take up to 60 seconds for a service account HMAC key to become useable.

## Get HMAC key information

To list the HMAC keys for a project, and get information about the keys:

### Console

1. In the Google Cloud console, go to the Cloud Storage **Settings** page.  

   [Go to Settings](https://console.cloud.google.com/storage/settings)
2. Select the **Interoperability** tab.

   Service accounts that have HMAC keys associated with them appear in the
   **Access keys for service accounts** subsection of the
   **Service account HMAC** section.
3. Click the name of a specific service account to see the HMAC keys
   associated with it and the status of those keys.

### Command line

1. Use the [`hmac list`](https://docs.cloud.google.com/sdk/gcloud/reference/storage/hmac/list) command to list hmac keys in your project:

   ```
   gcloud storage hmac list
   ```

   If successful, the command returns a list of hmac key access IDs,
   along with the state of each key and the service account associated
   with each key.
2. Use the [`hmac describe`](https://docs.cloud.google.com/sdk/gcloud/reference/storage/hmac/describe) command to retrieve metadata for a
   specific key:

   ```
   gcloud storage hmac describe KEY_ACCESS_ID 
   ```

   Where `KEY_ACCESS_ID` is the access ID for the
   key.

### Client libraries


### C++


For more information, see the
[Cloud Storage C++ API
reference documentation](https://docs.cloud.google.com/cpp/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```c++
namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client) {
  int count = 0;
  gcs::ListHmacKeysReader hmac_keys_list = client.ListHmacKeys();
  for (auto& key : hmac_keys_list) {
    if (!key) throw std::move(key).status();

    std::cout << "service_account_email = " << key->service_account_email()
              << "\naccess_id = " << key->access_id() << "\n";
    ++count;
  }
  if (count == 0) {
    std::cout << "No HMAC keys in default project\n";
  }
}
```

The following sample retrieves information for a specific HMAC key:

```c++
namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& access_id) {
  StatusOr<gcs::HmacKeyMetadata> hmac_key = client.GetHmacKey(access_id);
  if (!hmac_key) throw std::move(hmac_key).status();

  std::cout << "The HMAC key metadata is: " << *hmac_key << "\n";
}
```

### C#


For more information, see the
[Cloud Storage C# API
reference documentation](https://cloud.google.com/dotnet/docs/reference/Google.Cloud.Storage.V1/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```c#

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;
using System.Collections.Generic;

public class ListHmacKeysSample
{
    public IEnumerable<HmacKeyMetadata> ListHmacKeys(string projectId = "your-project-id")
    {
        var storage = StorageClient.Create();
        var keys = storage.ListHmacKeys(projectId);

        foreach (var key in keys)
        {
            Console.WriteLine($"Service Account Email: {key.ServiceAccountEmail}");
            Console.WriteLine($"Access ID: {key.AccessId}");
        }
        return keys;
    }
}
```

The following sample retrieves information for a specific HMAC key:

```c#

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;

public class GetHmacKeySample
{
    public HmacKeyMetadata GetHmacKey(
        string projectId = "your-project-id",
        string accessId = "your-access-id")
    {
        var storage = StorageClient.Create();
        var metadata = storage.GetHmacKey(projectId, accessId);

        Console.WriteLine("The HMAC key metadata is:");
        Console.WriteLine($"ID: {metadata.Id}");
        Console.WriteLine($"Access ID: {metadata.AccessId}");
        Console.WriteLine($"Project ID: {metadata.ProjectId}");
        Console.WriteLine($"Service Account Email: {metadata.ServiceAccountEmail}");
        Console.WriteLine($"State: {metadata.State}");
        Console.WriteLine($"Time Created: {metadata.TimeCreated}");
        Console.WriteLine($"Time Updated: {metadata.Updated}");
        Console.WriteLine($"ETag: {metadata.ETag}");
        return metadata;
    }
}
```

### Go


For more information, see the
[Cloud Storage Go API
reference documentation](https://pkg.go.dev/cloud.google.com/go/storage).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
	"google.golang.org/api/iterator"
)

// listHMACKeys lists all HMAC keys associated with the project.
func listHMACKeys(w io.Writer, projectID string) ([]*storage.HMACKey, error) {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	iter := client.ListHMACKeys(ctx, projectID)
	var keys []*storage.HMACKey
	for {
		key, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return nil, fmt.Errorf("ListHMACKeys: %w", err)
		}
		fmt.Fprintf(w, "Service Account Email: %s\n", key.ServiceAccountEmail)
		fmt.Fprintf(w, "Access ID: %s\n", key.AccessID)

		keys = append(keys, key)
	}

	return keys, nil
}
```

The following sample retrieves information for a specific HMAC key:

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// getHMACKey retrieves the HMACKeyMetadata with the given access id.
func getHMACKey(w io.Writer, accessID string, projectID string) (*storage.HMACKey, error) {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	handle := client.HMACKeyHandle(projectID, accessID)
	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	key, err := handle.Get(ctx)
	if err != nil {
		return nil, fmt.Errorf("Get: %w", err)
	}

	fmt.Fprintln(w, "The HMAC key metadata is:")
	fmt.Fprintf(w, "%+v", key)
	return key, nil
}
```

### Java


For more information, see the
[Cloud Storage Java API
reference documentation](https://cloud.google.com/java/docs/reference/google-cloud-storage/latest/overview).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```java

import com.google.api.gax.paging.Page;
import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;

public class ListHmacKeys {
  public static void listHmacKeys(String projectId) throws StorageException {
    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    Page<HmacKey.HmacKeyMetadata> page =
        storage.listHmacKeys(Storage.ListHmacKeysOption.projectId(projectId));

    for (HmacKey.HmacKeyMetadata metadata : page.iterateAll()) {
      System.out.println("Service Account Email: " + metadata.getServiceAccount().getEmail());
      System.out.println("Access ID: " + metadata.getAccessId());
    }
  }
}
```

The following sample retrieves information for a specific HMAC key:

```java

import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.util.Date;

public class GetHmacKey {
  public static void getHmacKey(String accessId, String projectId) throws StorageException {
    // The access ID of the HMAC key.
    // String accessId = "GOOG0234230X00";

    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    HmacKey.HmacKeyMetadata metadata =
        storage.getHmacKey(accessId, Storage.GetHmacKeyOption.projectId(projectId));

    System.out.println("The HMAC key metadata is:");
    System.out.println("ID: " + metadata.getId());
    System.out.println("Access ID: " + metadata.getAccessId());
    System.out.println("Project ID: " + metadata.getProjectId());
    System.out.println("Service Account Email: " + metadata.getServiceAccount().getEmail());
    System.out.println("State: " + metadata.getState().toString());
    System.out.println("Time Created: " + new Date(metadata.getCreateTime()).toString());
    System.out.println("Time Updated: " + new Date(metadata.getUpdateTime()).toString());
    System.out.println("ETag: " + metadata.getEtag());
  }
}
```

### Node.js


For more information, see the
[Cloud Storage Node.js API
reference documentation](https://cloud.google.com/nodejs/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// List HMAC SA Keys' Metadata
async function listHmacKeys() {
  const [hmacKeys] = await storage.getHmacKeys({projectId});

  // hmacKeys is an array of HmacKey objects.
  for (const hmacKey of hmacKeys) {
    console.log(
      `Service Account Email: ${hmacKey.metadata.serviceAccountEmail}`
    );
    console.log(`Access Id: ${hmacKey.metadata.accessId}`);
  }
}
```

The following sample retrieves information for a specific HMAC key:

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The access ID of the HMAC key
// const hmacKeyAccessId = 'GOOG0234230X00';

// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Get HMAC SA Key Metadata
async function getHmacKey() {
  const hmacKey = storage.hmacKey(hmacKeyAccessId, {projectId});

  // Populate the hmacKey object with metadata from server.
  await hmacKey.getMetadata();

  console.log('The HMAC key metadata is:');
  for (const [key, value] of Object.entries(hmacKey.metadata)) {
    console.log(`${key}: ${value}`);
  }
}
```

### PHP


For more information, see the
[Cloud Storage PHP API
reference documentation](https://googleapis.github.io/google-cloud-php/#/docs/google-cloud/latest/storage/storageclient).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```php
use Google\Cloud\Storage\StorageClient;

/**
 * List HMAC keys.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 */
function list_hmac_keys(string $projectId): void
{
    $storage = new StorageClient();
    // By default hmacKeys will use the projectId used by StorageClient() to list HMAC Keys.
    $hmacKeys = $storage->hmacKeys(['projectId' => $projectId]);

    printf('HMAC Key\'s:' . PHP_EOL);
    foreach ($hmacKeys as $hmacKey) {
        printf('Service Account Email: %s' . PHP_EOL, $hmacKey->info()['serviceAccountEmail']);
        printf('Access Id: %s' . PHP_EOL, $hmacKey->info()['accessId']);
    }
}
```

The following sample retrieves information for a specific HMAC key:

```php
use Google\Cloud\Storage\StorageClient;

/**
 * Get an HMAC key.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 * @param string $accessId Access ID for an HMAC key. (e.g. 'GOOG0234230X00')
 */
function get_hmac_key(string $projectId, string $accessId): void
{
    $storage = new StorageClient();
    $hmacKey = $storage->hmacKey($accessId, $projectId);

    printf('HMAC key Metadata: %s' . PHP_EOL, print_r($hmacKey->info(), true));
}
```

### Python


For more information, see the
[Cloud Storage Python API
reference documentation](https://cloud.google.com/python/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```python
from google.cloud import storage


def list_keys(project_id):
    """
    List all HMAC keys associated with the project.
    """
    # project_id = "Your Google Cloud project ID"

    storage_client = storage.Client(project=project_id)
    hmac_keys = storage_client.list_hmac_keys(project_id=project_id)
    print("HMAC Keys:")
    for hmac_key in hmac_keys:
        print(
            f"Service Account Email: {hmac_key.service_account_email}"
        )
        print(f"Access ID: {hmac_key.access_id}")
    return hmac_keys

```

The following sample retrieves information for a specific HMAC key:

```python
from google.cloud import storage


def get_key(access_id, project_id):
    """
    Retrieve the HMACKeyMetadata with the given access id.
    """
    # project_id = "Your Google Cloud project ID"
    # access_id = "ID of an HMAC key"

    storage_client = storage.Client(project=project_id)

    hmac_key = storage_client.get_hmac_key_metadata(
        access_id, project_id=project_id
    )

    print("The HMAC key metadata is:")
    print(f"Service Account Email: {hmac_key.service_account_email}")
    print(f"Key ID: {hmac_key.id}")
    print(f"Access ID: {hmac_key.access_id}")
    print(f"Project ID: {hmac_key.project}")
    print(f"State: {hmac_key.state}")
    print(f"Created At: {hmac_key.time_created}")
    print(f"Updated At: {hmac_key.updated}")
    print(f"Etag: {hmac_key.etag}")
    return hmac_key

```

### Ruby


For more information, see the
[Cloud Storage Ruby API
reference documentation](https://googleapis.dev/ruby/google-cloud-storage/latest/Google/Cloud/Storage.html).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample retrieves a list of HMAC keys associated with a project:

```ruby
def list_hmac_keys
  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#hmac_keys uses the Storage client project_id
  hmac_keys = storage.hmac_keys

  puts "HMAC Keys:"
  hmac_keys.all do |hmac_key|
    puts "Service Account Email: #{hmac_key.service_account_email}"
    puts "Access ID: #{hmac_key.access_id}"
  end
end
```

The following sample retrieves information for a specific HMAC key:

```ruby
def get_hmac_key access_id:
  # The access ID of the HMAC key
  # access_id = "GOOG0234230X00"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#hmac_keys uses the Storage client project_id
  hmac_key = storage.hmac_key access_id

  puts "The HMAC key metadata is:"
  puts "Key ID:                #{hmac_key.id}"
  puts "Service Account Email: #{hmac_key.service_account_email}"
  puts "Access ID:             #{hmac_key.access_id}"
  puts "Project ID:            #{hmac_key.project_id}"
  puts "Active:                #{hmac_key.active?}"
  puts "Created At:            #{hmac_key.created_at}"
  puts "Updated At:            #{hmac_key.updated_at}"
  puts "Etag:                  #{hmac_key.etag}"
end
```

<br />

### REST APIs

### JSON API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the JSON API with a [`LIST` hmacKeys](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys/list.md.txt)
   request:

   ```
   curl -X GET \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json" \
     "https://storage.googleapis.com/storage/v1/projects/PROJECT_IDENTIFIER/hmacKeys"
   ```

   Where `PROJECT_IDENTIFIER` is the ID or number
   for the project associated with the keys you want to list. For
   example, `my-pet-project`.

### XML API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the XML API with a [`GET` HMAC Key](https://docs.cloud.google.com/storage/docs/xml-api/get-hmac-list.md.txt)
   request:

   ```
   curl -X GET \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     "https://storage.googleapis.com/?Action=ListAccessKeys&UserName=SERVICE_ACCOUNT_EMAIL"
   ```

   Where `SERVICE_ACCOUNT_EMAIL` is the email
   address associated with your service account. For example,
   `example-service-account@my-pet-project.iam.gserviceaccount.com`.

## Update the state of an HMAC key

To switch an HMAC key between being active and inactive:

### Console

1. In the Google Cloud console, go to the Cloud Storage **Settings** page.  

   [Go to Settings](https://console.cloud.google.com/storage/settings)
2. Select the **Interoperability** tab.

3. In the **Access keys for service accounts** subsection, click the name of
   the service account associated with the HMAC key whose status you want
   to update.

4. Click the status of the key you want to update.

   - If you are changing the key's state from Inactive to Active, click
     **Deactivate** in the window that appears.

   - If you are changing the key's state from Active to Inactive, no
     additional steps are required.

### Command line

Use the [`hmac update`](https://docs.cloud.google.com/sdk/gcloud/reference/storage/hmac/update) command:

```
gcloud storage hmac update ACCESS_KEY_ID STATE
```

Where:

- `ACCESS_KEY_ID` is the access ID associated with the key you are updating.
- `STATE` is either `--activate` or `--deactivate`.

If successful, the command returns the updated metadata of the HMAC key.

### Client libraries


### C++


For more information, see the
[Cloud Storage C++ API
reference documentation](https://docs.cloud.google.com/cpp/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```c++
namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& access_id) {
  StatusOr<gcs::HmacKeyMetadata> updated = client.UpdateHmacKey(
      access_id, gcs::HmacKeyMetadata().set_state(
                     gcs::HmacKeyMetadata::state_inactive()));
  if (!updated) throw std::move(updated).status();

  if (updated->state() != gcs::HmacKeyMetadata::state_inactive()) {
    throw std::runtime_error("The HMAC key is active, this is unexpected");
  }
  std::cout << "The HMAC key is now inactive\nFull metadata: " << *updated
            << "\n";
}
```

The following sample activates an HMAC key:

```c++
namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& access_id) {
  StatusOr<gcs::HmacKeyMetadata> updated = client.UpdateHmacKey(
      access_id,
      gcs::HmacKeyMetadata().set_state(gcs::HmacKeyMetadata::state_active()));
  if (!updated) throw std::move(updated).status();

  if (updated->state() != gcs::HmacKeyMetadata::state_active()) {
    throw std::runtime_error(
        "The HMAC key is NOT active, this is unexpected");
  }
  std::cout << "The HMAC key is now active\nFull metadata: " << *updated
            << "\n";
}
```

### C#


For more information, see the
[Cloud Storage C# API
reference documentation](https://cloud.google.com/dotnet/docs/reference/Google.Cloud.Storage.V1/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```c#

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;

public class DeactivateHmacKeySample
{
    public HmacKeyMetadata DeactivateHmacKey(
        string projectId = "your-project-id",
        string accessId = "your-access-id")
    {
        var storage = StorageClient.Create();
        var metadata = storage.GetHmacKey(projectId, accessId);
        metadata.State = HmacKeyStates.Inactive;
        var updatedMetadata = storage.UpdateHmacKey(metadata);

        Console.WriteLine("The HMAC key is now inactive.");
        Console.WriteLine("The HMAC key metadata is:");
        Console.WriteLine($"ID: {updatedMetadata.Id}");
        Console.WriteLine($"Access ID: {updatedMetadata.AccessId}");
        Console.WriteLine($"Project ID: {updatedMetadata.ProjectId}");
        Console.WriteLine($"Service Account Email: {updatedMetadata.ServiceAccountEmail}");
        Console.WriteLine($"State: {updatedMetadata.State}");
        Console.WriteLine($"Time Created: {updatedMetadata.TimeCreated}");
        Console.WriteLine($"Time Updated: {updatedMetadata.Updated}");
        Console.WriteLine($"ETag: {updatedMetadata.ETag}");
        return updatedMetadata;
    }
}
```

The following sample activates an HMAC key:

```c#

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;

public class ActivateHmacKeySample
{
    public HmacKeyMetadata ActivateHmacKey(
        string projectId = "your-project-id",
        string accessId = "access-id")
    {
        var storage = StorageClient.Create();
        var metadata = storage.GetHmacKey(projectId, accessId);
        metadata.State = HmacKeyStates.Active;
        var updatedMetadata = storage.UpdateHmacKey(metadata);

        Console.WriteLine("The HMAC key is now active.");
        Console.WriteLine("The HMAC key metadata is:");
        Console.WriteLine($"ID: {updatedMetadata.Id}");
        Console.WriteLine($"Access ID: {updatedMetadata.AccessId}");
        Console.WriteLine($"Project ID: {updatedMetadata.ProjectId}");
        Console.WriteLine($"Service Account Email: {updatedMetadata.ServiceAccountEmail}");
        Console.WriteLine($"State: {updatedMetadata.State}");
        Console.WriteLine($"Time Created: {updatedMetadata.TimeCreated}");
        Console.WriteLine($"Time Updated: {updatedMetadata.Updated}");
        Console.WriteLine($"ETag: {updatedMetadata.ETag}");
        return updatedMetadata;
    }
}
```

### Go


For more information, see the
[Cloud Storage Go API
reference documentation](https://pkg.go.dev/cloud.google.com/go/storage).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// deactivateHMACKey deactivates the HMAC key with the given access ID.
func deactivateHMACKey(w io.Writer, accessID string, projectID string) (*storage.HMACKey, error) {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	handle := client.HMACKeyHandle(projectID, accessID)
	key, err := handle.Update(ctx, storage.HMACKeyAttrsToUpdate{State: "INACTIVE"})
	if err != nil {
		return nil, fmt.Errorf("Update: %w", err)
	}

	fmt.Fprintln(w, "The HMAC key metadata is:")
	fmt.Fprintf(w, "%+v", key)

	return key, nil
}
```

The following sample activates an HMAC key:

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// activateHMACKey activates the HMAC key with the given access ID.
func activateHMACKey(w io.Writer, accessID string, projectID string) (*storage.HMACKey, error) {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	handle := client.HMACKeyHandle(projectID, accessID)
	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	key, err := handle.Update(ctx, storage.HMACKeyAttrsToUpdate{State: "ACTIVE"})
	if err != nil {
		return nil, fmt.Errorf("Update: %w", err)
	}

	fmt.Fprintln(w, "The HMAC key metadata is:")
	fmt.Fprintf(w, "%+v", key)

	return key, nil
}
```

### Java


For more information, see the
[Cloud Storage Java API
reference documentation](https://cloud.google.com/java/docs/reference/google-cloud-storage/latest/overview).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```java

import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.util.Date;

public class DeactivateHmacKey {
  public static void deactivateHmacKey(String accessId, String projectId) throws StorageException {
    // The access ID of the HMAC key.
    // String accessId = "GOOG0234230X00";

    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    HmacKey.HmacKeyMetadata metadata =
        storage.getHmacKey(accessId, Storage.GetHmacKeyOption.projectId(projectId));
    HmacKey.HmacKeyMetadata newMetadata =
        storage.updateHmacKeyState(metadata, HmacKey.HmacKeyState.INACTIVE);

    System.out.println("The HMAC key is now inactive.");
    System.out.println("The HMAC key metadata is:");
    System.out.println("ID: " + newMetadata.getId());
    System.out.println("Access ID: " + newMetadata.getAccessId());
    System.out.println("Project ID: " + newMetadata.getProjectId());
    System.out.println("Service Account Email: " + newMetadata.getServiceAccount().getEmail());
    System.out.println("State: " + newMetadata.getState().toString());
    System.out.println("Time Created: " + new Date(newMetadata.getCreateTime()).toString());
    System.out.println("Time Updated: " + new Date(newMetadata.getUpdateTime()).toString());
    System.out.println("ETag: " + newMetadata.getEtag());
  }
}
```

The following sample activates an HMAC key:

```java

import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.util.Date;

public class ActivateHmacKey {
  public static void activateHmacKey(String accessId, String projectId) throws StorageException {
    // The access ID of the HMAC key.
    // String accessId = "GOOG0234230X00";

    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    HmacKey.HmacKeyMetadata metadata =
        storage.getHmacKey(accessId, Storage.GetHmacKeyOption.projectId(projectId));
    HmacKey.HmacKeyMetadata newMetadata =
        storage.updateHmacKeyState(metadata, HmacKey.HmacKeyState.ACTIVE);

    System.out.println("The HMAC key is now active.");
    System.out.println("The HMAC key metadata is:");
    System.out.println("ID: " + newMetadata.getId());
    System.out.println("Access ID: " + newMetadata.getAccessId());
    System.out.println("Project ID: " + newMetadata.getProjectId());
    System.out.println("Service Account Email: " + newMetadata.getServiceAccount().getEmail());
    System.out.println("State: " + newMetadata.getState().toString());
    System.out.println("Time Created: " + new Date(newMetadata.getCreateTime()).toString());
    System.out.println("Time Updated: " + new Date(newMetadata.getUpdateTime()).toString());
    System.out.println("ETag: " + newMetadata.getEtag());
  }
}
```

### Node.js


For more information, see the
[Cloud Storage Node.js API
reference documentation](https://cloud.google.com/nodejs/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The access ID of the HMAC key
// const hmacKeyAccessId = 'GOOG0234230X00';

// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Deactivate HMAC SA Key
async function deactivateHmacKey() {
  const hmacKey = storage.hmacKey(hmacKeyAccessId, {projectId});
  const [hmacKeyMetadata] = await hmacKey.setMetadata({state: 'INACTIVE'});

  console.log('The HMAC key is now inactive.');
  console.log('The HMAC key metadata is:');
  for (const [key, value] of Object.entries(hmacKeyMetadata)) {
    console.log(`${key}: ${value}`);
  }
}
```

The following sample activates an HMAC key:

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The access ID of the HMAC key
// const hmacKeyAccessId = 'GOOG0234230X00';

// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Activate HMAC SA Key
async function activateHmacKey() {
  const hmacKey = storage.hmacKey(hmacKeyAccessId, {projectId});
  const [hmacKeyMetadata] = await hmacKey.setMetadata({state: 'ACTIVE'});

  console.log('The HMAC key is now active.');
  console.log('The HMAC key metadata is:');
  for (const [key, value] of Object.entries(hmacKeyMetadata)) {
    console.log(`${key}: ${value}`);
  }
}
```

### PHP


For more information, see the
[Cloud Storage PHP API
reference documentation](https://googleapis.github.io/google-cloud-php/#/docs/google-cloud/latest/storage/storageclient).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```php
use Google\Cloud\Storage\StorageClient;

/**
 * Deactivate an HMAC key.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 * @param string $accessId Access ID for an inactive HMAC key.
 *        (e.g. 'GOOG0234230X00')
 */
function deactivate_hmac_key(string $projectId, string $accessId): void
{
    $storage = new StorageClient();
    // By default hmacKey will use the projectId used by StorageClient().
    $hmacKey = $storage->hmacKey($accessId, $projectId);

    $hmacKey->update('INACTIVE');

    print('The HMAC key is now inactive.' . PHP_EOL);
    printf('HMAC key Metadata: %s' . PHP_EOL, print_r($hmacKey->info(), true));
}
```

The following sample activates an HMAC key:

```php
use Google\Cloud\Storage\StorageClient;

/**
 * Activate an HMAC key.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 * @param string $accessId Access ID for an inactive HMAC key.
 *        (e.g. 'GOOG0234230X00')
 */
function activate_hmac_key(string $projectId, string $accessId): void
{
    $storage = new StorageClient();
    // By default hmacKey will use the projectId used by StorageClient().
    $hmacKey = $storage->hmacKey($accessId, $projectId);

    $hmacKey->update('ACTIVE');

    print('The HMAC key is now active.' . PHP_EOL);
    printf('HMAC key Metadata: %s' . PHP_EOL, print_r($hmacKey->info(), true));
}
```

### Python


For more information, see the
[Cloud Storage Python API
reference documentation](https://cloud.google.com/python/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```python
from google.cloud import storage


def deactivate_key(access_id, project_id):
    """
    Deactivate the HMAC key with the given access ID.
    """
    # project_id = "Your Google Cloud project ID"
    # access_id = "ID of an active HMAC key"

    storage_client = storage.Client(project=project_id)

    hmac_key = storage_client.get_hmac_key_metadata(
        access_id, project_id=project_id
    )
    hmac_key.state = "INACTIVE"
    hmac_key.update()

    print("The HMAC key is now inactive.")
    print("The HMAC key metadata is:")
    print(f"Service Account Email: {hmac_key.service_account_email}")
    print(f"Key ID: {hmac_key.id}")
    print(f"Access ID: {hmac_key.access_id}")
    print(f"Project ID: {hmac_key.project}")
    print(f"State: {hmac_key.state}")
    print(f"Created At: {hmac_key.time_created}")
    print(f"Updated At: {hmac_key.updated}")
    print(f"Etag: {hmac_key.etag}")
    return hmac_key

```

The following sample activates an HMAC key:

```python
from google.cloud import storage


def activate_key(access_id, project_id):
    """
    Activate the HMAC key with the given access ID.
    """
    # project_id = "Your Google Cloud project ID"
    # access_id = "ID of an inactive HMAC key"

    storage_client = storage.Client(project=project_id)

    hmac_key = storage_client.get_hmac_key_metadata(
        access_id, project_id=project_id
    )
    hmac_key.state = "ACTIVE"
    hmac_key.update()

    print("The HMAC key metadata is:")
    print(f"Service Account Email: {hmac_key.service_account_email}")
    print(f"Key ID: {hmac_key.id}")
    print(f"Access ID: {hmac_key.access_id}")
    print(f"Project ID: {hmac_key.project}")
    print(f"State: {hmac_key.state}")
    print(f"Created At: {hmac_key.time_created}")
    print(f"Updated At: {hmac_key.updated}")
    print(f"Etag: {hmac_key.etag}")
    return hmac_key

```

### Ruby


For more information, see the
[Cloud Storage Ruby API
reference documentation](https://googleapis.dev/ruby/google-cloud-storage/latest/Google/Cloud/Storage.html).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

The following sample deactivates an HMAC key:

```ruby
def deactivate_hmac_key access_id:
  # The access ID of the HMAC key
  # access_id = "GOOG0234230X00"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#hmac_keys uses the Storage client project_id
  hmac_key = storage.hmac_key access_id

  hmac_key.inactive!

  puts "The HMAC key is now inactive."
  puts "The HMAC key metadata is:"
  puts "Key ID:                #{hmac_key.id}"
  puts "Service Account Email: #{hmac_key.service_account_email}"
  puts "Access ID:             #{hmac_key.access_id}"
  puts "Project ID:            #{hmac_key.project_id}"
  puts "Active:                #{hmac_key.active?}"
  puts "Created At:            #{hmac_key.created_at}"
  puts "Updated At:            #{hmac_key.updated_at}"
  puts "Etag:                  #{hmac_key.etag}"
end
```

The following sample activates an HMAC key:

```ruby
def activate_hmac_key access_id:
  # The access ID of the HMAC key
  # access_id = "GOOG0234230X00"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#hmac_keys uses the Storage client project_id
  hmac_key = storage.hmac_key access_id

  hmac_key.active!

  puts "The HMAC key is now active."
  puts "The HMAC key metadata is:"
  puts "Key ID:                #{hmac_key.id}"
  puts "Service Account Email: #{hmac_key.service_account_email}"
  puts "Access ID:             #{hmac_key.access_id}"
  puts "Project ID:            #{hmac_key.project_id}"
  puts "Active:                #{hmac_key.active?}"
  puts "Created At:            #{hmac_key.created_at}"
  puts "Updated At:            #{hmac_key.updated_at}"
  puts "Etag:                  #{hmac_key.etag}"
end
```

<br />

### REST APIs

### JSON API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Create a JSON file that contains the following information:

   ```
   {"state": "STATE"}
   ```

   Where `STATE` is the target [state](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys/update.md.txt) for
   the key. For example, `INACTIVE`.
3. Use [`cURL`](http://curl.haxx.se/) to call the JSON API with a [`PUT` hmacKeys](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys/update.md.txt)
   request:

   ```
   curl -X PUT --data-binary @JSON_FILE_NAME \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json" \
     "https://storage.googleapis.com/storage/v1/projects/PROJECT_IDENTIFIER/hmacKeys/ACCESS_KEY_ID"
   ```

   Where:
   - `JSON_FILE_NAME` is the path for the file that you created in Step 2.
   - `PROJECT_IDENTIFIER` is the ID or number for the project associated with the key you want to update. For example, `my-pet-project`.
   - `ACCESS_KEY_ID` is the access ID associated with the key you are updating.

### XML API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the XML API with a [`POST` HMAC Key](https://docs.cloud.google.com/storage/docs/xml-api/post-hmac-update.md.txt)
   request:

   ```
   curl -X POST \
       -H "Authorization: Bearer $(gcloud auth print-access-token)" \
       "https://storage.googleapis.com/?Action=UpdateAccessKey&AccessKeyId=ACCESS_KEY_ID&Status=STATUS"
   ```

   Where:
   - `ACCESS_KEY_ID` is the access ID associated with the key you are updating.
   - `STATUS` is the target [status](https://docs.cloud.google.com/storage/docs/xml-api/post-hmac-update.md.txt#query_string_parameters) for the key. For example, `Inactive`.

When you change the state of an HMAC key, it takes up to 3 minutes for the
state change to propagate through the Cloud Storage system. For this
reason, you should wait at least 3 minutes between making an HMAC key inactive
and deleting the key.

## Delete an HMAC key

> [!CAUTION]
> **Caution:** HMAC keys cannot be recovered once you delete them. If you want to keep an HMAC key but prevent it from being used, [set its state](https://docs.cloud.google.com/storage/docs/authentication/managing-hmackeys.md.txt#update) to `INACTIVE`.

An HMAC key must be in an inactive state in order to delete it.
To delete an inactive HMAC key:

### Console

1. In the Google Cloud console, go to the Cloud Storage **Settings** page.  

   [Go to Settings](https://console.cloud.google.com/storage/settings)
2. Select the **Interoperability** tab.

3. In the **Access keys for service accounts** subsection, click the name of
   the service account associated with the HMAC key you want to delete.

4. Click the **Trash icon** associated with the key you want to delete.

5. In the dialog that appears, enter the first 10 characters of the
   access key ID as they are given in the window.

6. Click **Delete**.

### Command line

Use the [`hmac delete`](https://docs.cloud.google.com/sdk/gcloud/reference/storage/hmac/delete) command:

```
gcloud storage hmac delete ACCESS_KEY_ID
```

Where `ACCESS_KEY_ID` is the access ID associated
with the key you are deleting.

If successful, the command does not return a response.

### Client libraries


### C++


For more information, see the
[Cloud Storage C++ API
reference documentation](https://docs.cloud.google.com/cpp/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```c++
namespace gcs = ::google::cloud::storage;
[](gcs::Client client, std::string const& access_id) {
  google::cloud::Status status = client.DeleteHmacKey(access_id);
  if (!status.ok()) throw std::runtime_error(status.message());

  std::cout << "The key is deleted, though it may still appear"
            << " in ListHmacKeys() results.\n";
}
```

### C#


For more information, see the
[Cloud Storage C# API
reference documentation](https://cloud.google.com/dotnet/docs/reference/Google.Cloud.Storage.V1/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```c#

using Google.Cloud.Storage.V1;
using System;

public class DeleteHmacKeySample
{
    public void DeleteHmacKey(
        string projectId = "your-project-id",
        string accessId = "your-access-id")
    {
        var storage = StorageClient.Create();
        storage.DeleteHmacKey(projectId, accessId);

        Console.WriteLine($"Key {accessId} was deleted.");
    }
}
```

### Go


For more information, see the
[Cloud Storage Go API
reference documentation](https://pkg.go.dev/cloud.google.com/go/storage).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```go
import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// deleteHMACKey deletes the HMAC key with the given access ID. Key must have state
// INACTIVE in order to succeed.
func deleteHMACKey(w io.Writer, accessID string, projectID string) error {
	ctx := context.Background()

	// Initialize client.
	client, err := storage.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close() // Closing the client safely cleans up background resources.

	handle := client.HMACKeyHandle(projectID, accessID)
	ctx, cancel := context.WithTimeout(ctx, time.Minute)
	defer cancel()
	if err = handle.Delete(ctx); err != nil {
		return fmt.Errorf("Delete: %w", err)
	}

	fmt.Fprintln(w, "The key is deleted, though it may still appear in ListHMACKeys results.")

	return nil
}
```

### Java


For more information, see the
[Cloud Storage Java API
reference documentation](https://cloud.google.com/java/docs/reference/google-cloud-storage/latest/overview).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```java

import com.google.cloud.storage.HmacKey;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;

public class DeleteHmacKey {
  public static void deleteHmacKey(String accessId, String projectId) throws StorageException {

    // The access ID of the HMAC key.
    // String accessId = "GOOG0234230X00";

    // The ID of the project to which the service account belongs.
    // String projectId = "project-id";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    HmacKey.HmacKeyMetadata metadata =
        storage.getHmacKey(accessId, Storage.GetHmacKeyOption.projectId(projectId));
    storage.deleteHmacKey(metadata);

    System.out.println(
        "The key is deleted, though it will still appear in "
            + "getHmacKeys() results if called with showDeletedKey.");
  }
}
```

### Node.js


For more information, see the
[Cloud Storage Node.js API
reference documentation](https://cloud.google.com/nodejs/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```javascript
/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The access ID of the HMAC key
// const hmacKeyAccessId = 'GOOG0234230X00';

// The ID of the project to which the service account belongs
// const projectId = 'project-id';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Delete HMAC SA Key
async function deleteHmacKey() {
  const hmacKey = storage.hmacKey(hmacKeyAccessId, {projectId});
  await hmacKey.delete();

  console.log(
    'The key is deleted, though it may still appear in getHmacKeys() results.'
  );
}
```

### PHP


For more information, see the
[Cloud Storage PHP API
reference documentation](https://googleapis.github.io/google-cloud-php/#/docs/google-cloud/latest/storage/storageclient).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```php
use Google\Cloud\Storage\StorageClient;

/**
 * Delete an HMAC key.
 *
 * @param string $projectId The ID of your Google Cloud Platform project.
 *        (e.g. 'my-project-id')
 * @param string $accessId Access ID for an HMAC key. (e.g. 'GOOG0234230X00')
 */
function delete_hmac_key(string $projectId, string $accessId): void
{
    $storage = new StorageClient();
    // By default hmacKey will use the projectId used by StorageClient().
    $hmacKey = $storage->hmacKey($accessId, $projectId);

    $hmacKey->delete();
    print(
        'The key is deleted, though it may still appear in the results of calls ' .
        'to StorageClient.hmacKeys([\'showDeletedKeys\' => true])' . PHP_EOL
    );
}
```

### Python


For more information, see the
[Cloud Storage Python API
reference documentation](https://cloud.google.com/python/docs/reference/storage/latest).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```python
from google.cloud import storage


def delete_key(access_id, project_id):
    """
    Delete the HMAC key with the given access ID. Key must have state INACTIVE
    in order to succeed.
    """
    # project_id = "Your Google Cloud project ID"
    # access_id = "ID of an HMAC key (must be in INACTIVE state)"

    storage_client = storage.Client(project=project_id)

    hmac_key = storage_client.get_hmac_key_metadata(
        access_id, project_id=project_id
    )
    hmac_key.delete()

    print(
        "The key is deleted, though it may still appear in list_hmac_keys()"
        " results."
    )

```

### Ruby


For more information, see the
[Cloud Storage Ruby API
reference documentation](https://googleapis.dev/ruby/google-cloud-storage/latest/Google/Cloud/Storage.html).


To authenticate to Cloud Storage, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/storage/docs/authentication.md.txt#client-libs).

```ruby
def delete_hmac_key access_id:
  # The access ID of the HMAC key
  # access_id = "GOOG0234230X00"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  # By default Storage#hmac_keys uses the Storage client project_id
  hmac_key = storage.hmac_key access_id

  hmac_key.delete!

  puts "The key is deleted, though it may still appear in Client#hmac_keys results."
end
```

<br />

### REST APIs

### JSON API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the JSON API with a [`DELETE` hmacKeys](https://docs.cloud.google.com/storage/docs/json_api/v1/projects/hmacKeys/delete.md.txt)
   request:

   ```
   curl -X DELETE \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     "https://storage.googleapis.com/storage/v1/projects/PROJECT_IDENTIFIER/hmacKeys/ACCESS_KEY_ID"
   ```

   Where:
   - `PROJECT_IDENTIFIER` is the ID or number for the project associated with the key you want to delete. For example, `my-pet-project`.
   - `ACCESS_KEY_ID` is the access ID associated with the key you are deleting.

### XML API

1. Have gcloud CLI [installed and initialized](https://docs.cloud.google.com/sdk/docs/install), which lets
   you generate an access token for the `Authorization` header.

2. Use [`cURL`](http://curl.haxx.se/) to call the XML API with a [`POST` HMAC Key](https://docs.cloud.google.com/storage/docs/xml-api/post-hmac-delete.md.txt)
   request:

   ```
   curl -X POST \
       -H "Authorization: Bearer $(gcloud auth print-access-token)" \
       "https://storage.googleapis.com/?Action=DeleteAccessKey&AccessKeyId=ACCESS_KEY_ID"
   ```

   Where `ACCESS_KEY_ID` is the access ID
   associated with the key you are deleting.

## What's next

- Follow the [guidelines for migrating](https://docs.cloud.google.com/storage/docs/authentication/hmackeys.md.txt#migration) from user account HMAC keys to service account HMAC keys.
- [Use an HMAC key in an authenticated request](https://docs.cloud.google.com/storage/docs/aws-simple-migration.md.txt#authentication).