---
layout: docs
page_title: GCP Cloud KMS - Seals - Configuration
description: >-
  The GCP Cloud KMS seal configures Vault to use GCP Cloud KMS as the seal
  wrapping

  mechanism.
---

# `gcpckms` seal

-> **Note:** The Seal Wrap functionality is enabled by default. For this reason, the KMS service must be available throughout Vault's runtime and not just during the unseal process. Refer to the [Seal Wrap](/vault/docs/enterprise/sealwrap) documenation for more information.

The GCP Cloud KMS seal configures Vault to use GCP Cloud KMS as the seal
wrapping mechanism. The GCP Cloud KMS seal is activated by one of the following:

- The presence of a `seal "gcpckms"` block in Vault's configuration file.
- The presence of the environment variable `VAULT_SEAL_TYPE` set to `gcpckms`.
  If enabling via environment variable, all other required values specific to
  Cloud KMS (i.e. `VAULT_GCPCKMS_SEAL_KEY_RING`, etc.) must be also supplied, as
  well as all other GCP-related environment variables that lends to successful
  authentication (i.e. `GOOGLE_PROJECT`, etc.).

## `gcpckms` example

This example shows configuring GCP Cloud KMS seal through the Vault
configuration file by providing all the required values:

```hcl
seal "gcpckms" {
  credentials = "/usr/vault/vault-project-user-creds.json"
  project     = "vault-project"
  region      = "global"
  key_ring    = "vault-keyring"
  crypto_key  = "vault-key"
}
```

## `gcpckms` parameters

These parameters apply to the `seal` stanza in the Vault configuration file:

- `credentials` `(string: <required>)`: The path to the credentials JSON file
  to use. May be also specified by the `GOOGLE_CREDENTIALS` or
  `GOOGLE_APPLICATION_CREDENTIALS` environment variable or set automatically if
  running under Google App Engine, Google Compute Engine or Google Kubernetes
  Engine.

- `project` `(string: <required>)`: The GCP project ID to use. May also be
  specified by the `GOOGLE_PROJECT` environment variable.

- `region` `(string: <required>)`: The GCP region/location where the key ring
  lives. May also be specified by the `GOOGLE_REGION` environment variable.

- `key_ring` `(string: <required>)`: The GCP CKMS key ring to use. May also be
  specified by the `VAULT_GCPCKMS_SEAL_KEY_RING` environment variable.

- `crypto_key` `(string: <required>)`: The GCP CKMS crypto key to use for
  encryption and decryption. May also be specified by the
  `VAULT_GCPCKMS_SEAL_CRYPTO_KEY` environment variable.

- `disabled` `(string: "")`: Set this to `true` if Vault is migrating from an auto seal configuration. Otherwise, set to `false`.

Refer to the [Seal Migration](/vault/docs/concepts/seal#seal-migration) documentation for more information about the seal migration process.

## Authentication &amp; permissions

Authentication-related values must be provided, either as environment
variables or as configuration parameters.

GCP authentication values:

- `GOOGLE_CREDENTIALS` or `GOOGLE_APPLICATION_CREDENTIALS`
- `GOOGLE_PROJECT`
- `GOOGLE_REGION`

Note: The client uses the official Google SDK and will use the specified
credentials, environment credentials, or [application default
credentials](https://developers.google.com/identity/protocols/application-default-credentials)
in that order, if the above GCP specific values are not provided.

The service account needs the following minimum permissions on the crypto key:

```text
cloudkms.cryptoKeyVersions.useToEncrypt
cloudkms.cryptoKeyVersions.useToDecrypt
cloudkms.cryptoKeys.get
```

These permissions can be described with the following role:

```text
roles/cloudkms.cryptoKeyEncrypterDecrypter
cloudkms.cryptoKeys.get
```

`cloudkms.cryptoKeys.get` permission is used for retrieving metadata information of keys from CloudKMS within this engine initialization process.

## `gcpckms` environment variables

Alternatively, the GCP Cloud KMS seal can be activated by providing the following
environment variables:

- `VAULT_SEAL_TYPE`
- `VAULT_GCPCKMS_SEAL_KEY_RING`
- `VAULT_GCPCKMS_SEAL_CRYPTO_KEY`

## Key rotation

This seal supports rotating keys defined in Google Cloud KMS
[doc](https://cloud.google.com/kms/docs/rotating-keys). Both scheduled rotation and manual
rotation is supported for CKMS since the key information. Old keys version must not be
disabled or deleted and are used to decrypt older data. Any new or updated data will be
encrypted with the primary key version.

## Tutorial

Refer to the [Auto-unseal using GCP Cloud KMS](/vault/tutorials/auto-unseal/autounseal-gcp-kms)
guide for a step-by-step tutorial.
