---
layout: docs
page_title: Key management secrets engine
description: >-
  Create a consistent workflow for distribution and lifecycle management of cryptographic keys in various key management service (KMS) providers.
---

# Key management secrets engine

@include 'alerts/enterprise-and-hcp.mdx'

Key management secrets engine requires [Vault
Enterprise](https://www.hashicorp.com/products/vault/pricing) with the Advanced Data
Protection (ADP) module.

The key management secrets engine provides a consistent workflow for distribution and lifecycle
management of cryptographic keys in various key management service (KMS) providers. It allows
organizations to maintain centralized control of their keys in Vault while still taking advantage
of cryptographic capabilities native to the KMS providers.

The secrets engine generates and owns original copies of key material. When an operator decides
to distribute and manage the lifecycle of a key in one of the [supported KMS providers](#kms-providers),
a copy of the key material is distributed. This provides additional durability and disaster
recovery means for the complete lifecycle of the key in the KMS provider.

Key material will always be securely transferred in accordance with the
[key import specification](#kms-providers) of the supported KMS providers.

## Setup

Most secrets engines must be configured in advance before they can perform their
functions. These steps are usually completed by an operator or configuration
management tool.

1. Enable the key management secrets engine:

   ```shell-session
   $ vault secrets enable keymgmt
   Success! Enabled the keymgmt secrets engine at: keymgmt/
   ```

   By default, the secrets engine will mount at the name of the engine. To enable
   the secrets engine at a different path, use the `-path` argument.

## Usage

After the secrets engine is mounted and a user/machine has a Vault token with
the proper permission, it can use this secrets engine to generate, distribute, and
manage the lifecycle of cryptographic keys in [supported KMS providers](#kms-providers).

1. Create a named cryptographic key of a specified type:

   ```shell-session
   $ vault write -f keymgmt/key/example-key type="rsa-2048"
   Success! Data written to: keymgmt/key/example-key
   ```

   Keys created by the secrets engine are considered general-purpose until
   they're distributed to a KMS provider.

1. Configure a KMS provider:

   ```shell-session
   $ vault write keymgmt/kms/example-kms \
       provider="azurekeyvault" \
       key_collection="keyvault-name" \
       credentials=client_id="a0454cd1-e28e-405e-bc50-7477fa8a00b7" \
       credentials=client_secret="eR%HizuCVEpAKgeaUEx" \
       credentials=tenant_id="cd4bf224-d114-4f96-9bbc-b8f45751c43f"
   ```

   Conceptually, a KMS provider resource represents a destination for keys to be distributed to
   and subsequently managed in. It is configured using a generic set of parameters. The values
   supplied to the generic set of parameters will differ depending on the specified `provider`.

   This operation creates a KMS provider that represents a named Azure Key Vault instance.
   This is accomplished by specifying the `azurekeyvault` provider along with other provider-specific
   parameter values. For details on how to configure each supported KMS provider, see the
   [KMS Providers](#kms-providers) section.

1. Distribute a key to a KMS provider:

   ```shell-session
   $ vault write keymgmt/kms/example-kms/key/example-key \
       purpose="encrypt,decrypt" \
       protection="hsm"
   ```

   This operation distributes a **copy** of the named key to the KMS provider with a specific
   `purpose` and `protection`. The `purpose` defines the set of cryptographic capabilities
   that the key will have in the KMS provider. The `protection` defines where cryptographic
   operations are performed with the key in the KMS provider. See the API documentation for a list of
   supported [purpose](/vault/api-docs/secret/key-management#purpose) and [protection](/vault/api-docs/secret/key-management#protection)
   values.

   ~> **Note:** The amount of time it takes to distribute a key to a KMS provider is proportional to the
   number of versions that the key has. If a timeout occurs when distributing a key to a KMS
   provider, you may need to increase the [VAULT_CLIENT_TIMEOUT](/vault/docs/commands#vault_client_timeout).

1. Rotate a key:

   ```shell-session
   $ vault write -f keymgmt/key/example-key/rotate
   ```

   Rotating a key creates a new key version that contains new key material. The key will be rotated
   in both Vault and the KMS provider that the key has been distributed to. The new key version
   will be enabled and set as the current version for cryptographic operations in the KMS provider.

1. Enable or disable key versions:

   ```shell-session
   $ vault write keymgmt/key/example-key min_enabled_version=2
   ```

   The `min_enabled_version` of a key can be updated in order to enable or disable sequences of
   key versions. All versions of the key less than the `min_enabled_version` will be disabled for
   cryptographic operations in the KMS provider that the key has been distributed to. Setting a
   `min_enabled_version` of `0` means that all key versions will be enabled.

1. Remove a key from a KMS provider:

   ```shell-session
   $ vault delete keymgmt/kms/example-kms/key/example-key
   ```

   This operation results in the key being deleted from the KMS provider. The key will still exist
   in the secrets engine and can be redistributed to a KMS provider at a later time.

   To permanently delete the key from the secrets engine, the [delete key](/vault/api-docs/secret/key-management#delete-key)
   API may be invoked.

## Key types

The key management secrets engine supports generation of the following key types:

- `aes256-gcm96` - AES-GCM with a 256-bit AES key and a 96-bit nonce (symmetric)
- `rsa-2048` - RSA with bit size of 2048 (asymmetric)
- `rsa-3072` - RSA with bit size of 3072 (asymmetric)
- `rsa-4096` - RSA with bit size of 4096 (asymmetric)
- `ecdsa-p256` - ECDSA using the P-256 elliptic curve (asymmetric)
- `ecdsa-p384` - ECDSA using the P-384 elliptic curve (asymmetric)
- `ecdsa-p521` - ECDSA using the P-521 elliptic curve (asymmetric)

## KMS providers

The key management secrets engine supports lifecycle management of keys in the following
KMS providers:

- [Azure Key Vault](/vault/docs/secrets/key-management/azurekeyvault)
- [AWS KMS](/vault/docs/secrets/key-management/awskms)
- [GCP Cloud KMS](/vault/docs/secrets/key-management/gcpkms)

Refer to the provider-specific documentation for details on how to properly configure each provider.

## Compatibility

The following table defines which key types are compatible with each KMS provider.

| Key Type       | Azure Key Vault | AWS KMS | GCP Cloud KMS |
| -------------- | --------------- | ------- | ------------- |
| `aes256-gcm96` | No              | **Yes** | **Yes**       |
| `rsa-2048`     | **Yes**         | No      | **Yes**       |
| `rsa-3072`     | **Yes**         | No      | **Yes**       |
| `rsa-4096`     | **Yes**         | No      | **Yes**       |
| `ecdsa-p256`   | No              | No      | **Yes**       |
| `ecdsa-p384`   | No              | No      | **Yes**       |
| `ecdsa-p521`   | No              | No      | No            |

## API

The key management secrets engine has a full HTTP API. Please see the
[Key Management Secrets Engine API](/vault/api-docs/secret/key-management) for more
details.
