---
layout: docs
page_title: Azure Key Vault - Key Management - Secrets Engines
description: Key management secrets engine supports lifecycle management of keys in Azure Key Vault instances.
---

# Azure Key Vault

The key management secrets engine supports lifecycle management of keys in named
[Azure Key Vault](https://docs.microsoft.com/en-us/azure/key-vault/) instances.
This is accomplished by configuring a KMS provider resource with the `azurekeyvault`
provider and other provider-specific parameter values.

The following sections describe how to properly configure the secrets engine to enable
the functionality.

Refer to the [setup guide](/vault/docs/secrets/key-management/azurekeyvault/setup) for CLI command examples.

## Authentication

You need to configure the key management secrets engine with credentials that have sufficient
permissions to manage keys in an Azure Key Vault instance. The [credentials](/vault/api-docs/secret/key-management/azurekeyvault#credentials) section of the API documentation describes the authentication parameters. The authentication parameters will be set with the following order
of precedence:

1. Environment variables
2. [KMS provider credentials](/vault/api-docs/secret/key-management/azurekeyvault#credentials)
3. [Managed Service Identity (MSI)](https://docs.microsoft.com/en-us/azure/active-directory/managed-service-identity/overview)

If the client ID or secret are not provided and Vault is running on an Azure VM, Vault will attempt
to use MSI to access Azure. Note that when MSI is used, the tenant ID must still be explicitly provided by the configuration or environment variable.

An Azure Key Vault [access policy](https://docs.microsoft.com/en-us/azure/key-vault/general/assign-access-policy-portal) determines whether a given service principal, namely an application or user group, can perform certain operations on a Key Vault instance. The service principal associated with the provided credentials must have an access policy on the Key Vault instance with the following minimum key permissions:

- `create`
- `delete`
- `get`
- `import`
- `update`

<Tip title="Use Terraform">

If you are familiar with Terraform, you can use it to deploy the necessary Azure infrastructure. Refer to the [Terraform example](/vault/docs/secrets/key-management/azurekeyvault/setup#terraform-example) section.

</Tip>

## Key transfer specification

Keys are securely transferred from the secrets engine to Azure key vault instances in accordance
with the Azure [Bring Your Own Key](https://docs.microsoft.com/en-us/azure/key-vault/keys/byok-specification)
specification.

## Key purpose compatibility

The following table defines which key [purposes](/vault/api-docs/secret/key-management#purpose) can be used
for each key type supported by Azure Key Vault KMS.

| Key Type       | Purpose                                                 |
| -------------- | ------------------------------------------------------- |
| `rsa-2048`     | [All purposes](/vault/api-docs/secret/key-management#purpose) |
| `rsa-3072`     | [All purposes](/vault/api-docs/secret/key-management#purpose) |
| `rsa-4096`     | [All purposes](/vault/api-docs/secret/key-management#purpose) |
