# Azure Key Vault Keys client library for Python
Azure Key Vault helps solve the following problems:
- Cryptographic key management (this library) - create, store, and control
access to the keys used to encrypt your data
- Secrets management
([azure-keyvault-secrets](https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-secrets)) -
securely store and control access to tokens, passwords, certificates, API keys,
and other secrets
- Certificate management
([azure-keyvault-certificates](https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-certificates)) -
create, manage, and deploy public and private SSL/TLS certificates
- Vault administration ([azure-keyvault-administration](https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-administration)) - role-based access control (RBAC), and vault-level backup and restore options

[Source code][library_src]
| [Package (PyPI)][pypi_package_keys]
| [Package (Conda)](https://anaconda.org/microsoft/azure-keyvault/)
| [API reference documentation][reference_docs]
| [Product documentation][azure_keyvault]
| [Samples][key_samples]

## _Disclaimer_

_Azure SDK Python packages support for Python 2.7 has ended 01 January 2022. For more information and questions, please refer to https://github.com/Azure/azure-sdk-for-python/issues/20691_.

_Python 3.9 or later is required to use this package. For more details, please refer to [Azure SDK for Python version support policy](https://github.com/Azure/azure-sdk-for-python/blob/main/doc/python_version_support_policy.md)._

## Getting started
### Install the package
Install [azure-keyvault-keys][pypi_package_keys] and
[azure-identity][azure_identity_pypi] with [pip][pip]:
```Bash
pip install azure-keyvault-keys azure-identity
```
[azure-identity][azure_identity] is used for Azure Active Directory authentication as demonstrated below.

### Prerequisites
* An [Azure subscription][azure_sub]
* Python 3.9 or later
* An existing [Azure Key Vault][azure_keyvault]. If you need to create one, you can do so using the Azure CLI by following the steps in [this document][azure_keyvault_cli].
* If using Managed HSM, an existing [Key Vault Managed HSM][managed_hsm]. If you need to create a Managed HSM, you can do so using the Azure CLI by following the steps in [this document][managed_hsm_cli].

### Authenticate the client
In order to interact with the Azure Key Vault service, you will need an instance of a [KeyClient][key_client_docs], as
well as a **vault URL** and a credential object. This document demonstrates using a
[DefaultAzureCredential][default_cred_ref], which is appropriate for most scenarios. We recommend using a
[managed identity][managed_identity] for authentication in production environments.

See [azure-identity][azure_identity] documentation for more information about other methods of authentication and their
corresponding credential types.

#### Create a client
After configuring your environment for the [DefaultAzureCredential][default_cred_ref] to use a suitable method of
authentication, you can do the following to create a key client (replacing the value of `VAULT_URL` with your vault's
URL):

<!-- SNIPPET:hello_world.create_a_key_client -->

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

VAULT_URL = os.environ["VAULT_URL"]
credential = DefaultAzureCredential()
client = KeyClient(vault_url=VAULT_URL, credential=credential)
```

<!-- END SNIPPET -->

> **NOTE:** For an asynchronous client, import `azure.keyvault.keys.aio`'s `KeyClient` instead.

## Key concepts
### Keys
Azure Key Vault can create and store RSA and elliptic curve keys. Both can optionally be protected by hardware security
modules (HSMs). Azure Key Vault can also perform cryptographic operations with them. For more information about keys
and supported operations and algorithms, see the
[Key Vault documentation](https://learn.microsoft.com/azure/key-vault/keys/about-keys).

[KeyClient][key_client_docs] can create keys in the vault, get existing keys
from the vault, update key metadata, and delete keys, as shown in the
[examples](#examples) below.

## Examples
This section contains code snippets covering common tasks:
* [Create a key](#create-a-key)
* [Retrieve a key](#retrieve-a-key)
* [Update an existing key](#update-an-existing-key)
* [Delete a key](#delete-a-key)
* [Configure automatic key rotation](#configure-automatic-key-rotation)
* [Register external keys](#register-external-keys-managed-hsm-only)
* [List keys](#list-keys)
* [Perform cryptographic operations](#cryptographic-operations)
* [Async API](#async-api)
* [Asynchronously create a key](#asynchronously-create-a-key)
* [Asynchronously list keys](#asynchronously-list-keys)

### Create a key
The [create_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.create_key) method can be
used by a `KeyClient` to create a key of any type -- alternatively, specific helpers such as
[create_rsa_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.create_rsa_key) and
[create_ec_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.create_ec_key)
create RSA and elliptic curve keys in the vault, respectively. If a key with the same name already exists, a new version
of that key is created.

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)

# Create an RSA key
rsa_key = key_client.create_rsa_key("rsa-key-name", size=2048)
print(rsa_key.name)
print(rsa_key.key_type)

# Create an elliptic curve key
ec_key = key_client.create_ec_key("ec-key-name", curve="P-256")
print(ec_key.name)
print(ec_key.key_type)
```

### Retrieve a key
[get_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.get_key) retrieves a key
previously stored in the Vault.
```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
key = key_client.get_key("key-name")
print(key.name)
```

### Update an existing key
[update_key_properties](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.update_key_properties)
updates the properties of a key previously stored in the Key Vault.
```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)

# we will now disable the key for further use
updated_key = key_client.update_key_properties("key-name", enabled=False)

print(updated_key.name)
print(updated_key.properties.enabled)
```

### Delete a key
[begin_delete_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.begin_delete_key)
requests Key Vault delete a key, returning a poller which allows you to wait for the deletion to finish. Waiting is
helpful when the vault has [soft-delete][soft_delete] enabled, and you want to purge (permanently delete) the key as
soon as possible. When [soft-delete][soft_delete] is disabled, `begin_delete_key` itself is permanent.

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
deleted_key = key_client.begin_delete_key("key-name").result()

print(deleted_key.name)
print(deleted_key.deleted_date)
```

### Configure automatic key rotation
[update_key_rotation_policy](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.update_key_rotation_policy)
can be used by a `KeyClient` to configure automatic key rotation for a key by specifying a rotation policy.

<!-- SNIPPET:key_rotation.update_a_rotation_policy -->

```python
from azure.keyvault.keys import KeyRotationLifetimeAction, KeyRotationPolicy, KeyRotationPolicyAction

# Here we set the key's automated rotation policy to rotate the key two months after the key was created.
# If you pass an empty KeyRotationPolicy() as the `policy` parameter, the rotation policy will be set to the
# default policy. Any keyword arguments will update specified properties of the policy.
actions = [KeyRotationLifetimeAction(KeyRotationPolicyAction.rotate, time_after_create="P2M")]
updated_policy = client.update_key_rotation_policy(
    "rotation-sample-key", policy=KeyRotationPolicy(), expires_in="P90D", lifetime_actions=actions
)
assert updated_policy.expires_in == "P90D"
```

<!-- END SNIPPET -->

In addition,
[rotate_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.rotate_key)
allows you to rotate a key on-demand by creating a new version of the given key.

<!-- SNIPPET:key_rotation.rotate_key -->

```python
rotated_key = client.rotate_key("rotation-sample-key")
print(f"Rotated the key on-demand; new version is {rotated_key.properties.version}")
```

<!-- END SNIPPET -->

### Register external keys (Managed HSM only)
[create_external_key](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.create_external_key)
registers an external key with a Managed HSM that is configured to use External Key Management (EKM). The external HSM
owns the key material; the Managed HSM stores only a reference to the key.

> **NOTE:** External keys are only supported on Managed HSM, not regular Key Vault. The Managed HSM must be configured
> with an external HSM source.

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import ExternalKey, KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-managed-hsm.managedhsm.azure.net/", credential=credential)

external_key = ExternalKey(id="external-key-reference-id")
key = key_client.create_external_key("external-key-name", external_key=external_key)

print(key.name)
print(key.properties.external_key.id)
```

### List keys
[list_properties_of_keys](https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient.list_properties_of_keys)
lists the properties of all of the keys in the client's vault.

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient

credential = DefaultAzureCredential()

key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
keys = key_client.list_properties_of_keys()

for key in keys:
    # the list doesn't include values or versions of the keys
    print(key.name)
```

### Cryptographic operations
[CryptographyClient](https://aka.ms/azsdk/python/keyvault-keys/crypto/docs#azure.keyvault.keys.crypto.CryptographyClient)
enables cryptographic operations (encrypt/decrypt, wrap/unwrap, sign/verify) using a particular key.

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient
from azure.keyvault.keys.crypto import CryptographyClient, EncryptionAlgorithm

credential = DefaultAzureCredential()
key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)

key = key_client.get_key("key-name")
crypto_client = CryptographyClient(key, credential=credential)
plaintext = b"plaintext"

result = crypto_client.encrypt(EncryptionAlgorithm.rsa_oaep_256, plaintext)
decrypted = crypto_client.decrypt(result.algorithm, result.ciphertext)
```

See the
[package documentation][crypto_client_docs]
for more details of the cryptography API.

### Async API
This library includes a complete set of async APIs. To use them, you must
first install an async transport, such as [aiohttp](https://pypi.org/project/aiohttp/).
See
[azure-core documentation](https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/core/azure-core/CLIENT_LIBRARY_DEVELOPER.md#transport)
for more information.

Async clients and credentials should be closed when they're no longer needed. These
objects are async context managers and define async `close` methods. For
example:

```python
from azure.identity.aio import DefaultAzureCredential
from azure.keyvault.keys.aio import KeyClient

credential = DefaultAzureCredential()

# call close when the client and credential are no longer needed
client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
...
await client.close()
await credential.close()

# alternatively, use them as async context managers (contextlib.AsyncExitStack can help)
client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
async with client:
  async with credential:
    ...
```

### Asynchronously create a key
[create_rsa_key](https://aka.ms/azsdk/python/keyvault-keys/aio/docs#azure.keyvault.keys.aio.KeyClient.create_rsa_key) and
[create_ec_key](https://aka.ms/azsdk/python/keyvault-keys/aio/docs#azure.keyvault.keys.aio.KeyClient.create_ec_key)
create RSA and elliptic curve keys in the vault, respectively. If a key with the same name already exists, a new
version of the key is created.

```python
from azure.identity.aio import DefaultAzureCredential
from azure.keyvault.keys.aio import KeyClient

credential = DefaultAzureCredential()
key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)

# Create an RSA key
rsa_key = await key_client.create_rsa_key("rsa-key-name", size=2048)
print(rsa_key.name)
print(rsa_key.key_type)

# Create an elliptic curve key
ec_key = await key_client.create_ec_key("ec-key-name", curve="P-256")
print(ec_key.name)
print(ec_key.key_type)
```

### Asynchronously list keys
[list_properties_of_keys](https://aka.ms/azsdk/python/keyvault-keys/aio/docs#azure.keyvault.keys.aio.KeyClient.list_properties_of_keys)
lists the properties of all of the keys in the client's vault.

```python
from azure.identity.aio import DefaultAzureCredential
from azure.keyvault.keys.aio import KeyClient

credential = DefaultAzureCredential()
key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)
keys = key_client.list_properties_of_keys()

async for key in keys:
    print(key.name)
```

## Troubleshooting

See the `azure-keyvault-keys`
[troubleshooting guide](https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/TROUBLESHOOTING.md)
for details on how to diagnose various failure scenarios.

### General
Key Vault clients raise exceptions defined in [azure-core][azure_core_exceptions].
For example, if you try to get a key that doesn't exist in the vault, [KeyClient][key_client_docs]
raises [ResourceNotFoundError](https://aka.ms/azsdk-python-core-exceptions-resource-not-found-error):

```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient
from azure.core.exceptions import ResourceNotFoundError

credential = DefaultAzureCredential()
key_client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential)

try:
    key_client.get_key("which-does-not-exist")
except ResourceNotFoundError as e:
    print(e.message)
```

### Logging
This library uses the standard
[logging](https://docs.python.org/3/library/logging.html) library for logging.
Basic information about HTTP sessions (URLs, headers, etc.) is logged at INFO
level.

Detailed DEBUG level logging, including request/response bodies and unredacted
headers, can be enabled on a client with the `logging_enable` argument:
```python
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient
import sys
import logging

# Create a logger for the 'azure' SDK
logger = logging.getLogger('azure')
logger.setLevel(logging.DEBUG)

# Configure a console output
handler = logging.StreamHandler(stream=sys.stdout)
logger.addHandler(handler)

credential = DefaultAzureCredential()

# This client will log detailed information about its HTTP sessions, at DEBUG level
client = KeyClient(vault_url="https://my-key-vault.vault.azure.net/", credential=credential, logging_enable=True)
```

Similarly, `logging_enable` can enable detailed logging for a single operation,
even when it isn't enabled for the client:
```python
client.get_key("my-key", logging_enable=True)
```

## Next steps
Several samples are available in the Azure SDK for Python GitHub repository.
These provide example code for additional Key Vault scenarios:

- [Create/get/update/delete keys][hello_world_sample] ([async version][hello_world_async_sample])
- [Basic list operations for keys][list_operations_sample] ([async version][list_operations_async_sample])
- [Back up and recover keys][backup_operations_sample] ([async version][backup_operations_async_sample])
- [Recover and purge keys][recover_purge_sample] ([async version][recover_purge_async_sample])
- [Create/update key rotation policies and rotate keys on-demand][key_rotation_sample] ([async version][key_rotation_async_sample])
- [Use the `send_request` client method][send_request_sample]

###  Additional documentation
For more extensive documentation on Azure Key Vault, see the
[API reference documentation][reference_docs].

## Contributing
This project welcomes contributions and suggestions. Most contributions require
you to agree to a Contributor License Agreement (CLA) declaring that you have
the right to, and actually do, grant us the rights to use your contribution.
For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether
you need to provide a CLA and decorate the PR appropriately (e.g., label,
comment). Simply follow the instructions provided by the bot. You will only
need to do this once across all repos using our CLA.

This project has adopted the [Microsoft Open Source Code of Conduct][code_of_conduct].
For more information, see the
[Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
contact opencode@microsoft.com with any additional questions or comments.


<!-- LINKS -->
[azure_core_exceptions]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/core/azure-core#azure-core-library-exceptions
[azure_identity]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/identity/azure-identity
[azure_identity_pypi]: https://pypi.org/project/azure-identity/
[azure_keyvault]: https://learn.microsoft.com/azure/key-vault/
[azure_keyvault_cli]: https://learn.microsoft.com/azure/key-vault/general/quick-create-cli
[azure_sub]: https://azure.microsoft.com/free/

[backup_operations_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/backup_restore_operations.py
[backup_operations_async_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/backup_restore_operations_async.py

[code_of_conduct]: https://opensource.microsoft.com/codeofconduct/
[crypto_client_docs]: https://aka.ms/azsdk/python/keyvault-keys/crypto/docs

[default_cred_ref]: https://aka.ms/azsdk/python/identity/docs#azure.identity.DefaultAzureCredential

[hello_world_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/hello_world.py
[hello_world_async_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/hello_world_async.py

[key_client_docs]: https://aka.ms/azsdk/python/keyvault-keys/docs#azure.keyvault.keys.KeyClient
[key_rotation_sample]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/samples/key_rotation.py
[key_rotation_async_sample]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/samples/key_rotation_async.py
[key_samples]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/samples

[library_src]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/azure/keyvault/keys
[list_operations_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/list_operations.py
[list_operations_async_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/list_operations_async.py

[managed_hsm]: https://learn.microsoft.com/azure/key-vault/managed-hsm/overview
[managed_hsm_cli]: https://learn.microsoft.com/azure/key-vault/managed-hsm/quick-create-cli
[managed_identity]: https://learn.microsoft.com/azure/active-directory/managed-identities-azure-resources/overview

[pip]: https://pypi.org/project/pip/
[pypi_package_keys]: https://pypi.org/project/azure-keyvault-keys/

[recover_purge_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/recover_purge_operations.py
[recover_purge_async_sample]: https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/keyvault/azure-keyvault-keys/samples/recover_purge_operations_async.py
[reference_docs]: https://aka.ms/azsdk/python/keyvault-keys/docs

[send_request_sample]: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/keyvault/azure-keyvault-keys/samples/send_request.py
[soft_delete]: https://learn.microsoft.com/azure/key-vault/general/soft-delete-overview


