---
layout: docs
page_title: Vault Enterprise Seal Wrap
description: |-
  Vault Enterprise features a mechanism to wrap values with an extra layer of
  encryption for supporting seals.
---

# Seal wrap

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

Vault Enterprise features a mechanism to wrap values with an extra layer of
encryption for supporting [seals](/vault/docs/configuration/seal). This adds an
extra layer of protection and is useful in some compliance and regulatory
environments, including FIPS 140-2 environments.

To use this feature, you must have an active or trial license for Vault
Enterprise Plus (HSMs). To start a trial, contact [HashiCorp
sales](mailto:sales@hashicorp.com).

## Enabling/Disabling

Seal Wrap is enabled by default on supporting seals. This implies that the seal
must be available throughout Vault's runtime. Most cloud-based seals should be
quite reliable, but, for instance, if using an HSM in a non-HA setup a
connection interruption to the HSM will result in issues with Vault
functionality.

To disable seal wrapping, set `disable_sealwrap = true` in Vault's
[configuration file][configuration]. This will not affect auto-unsealing functionality; Vault's
root key will still be protected by the seal wrapping mechanism. It will
simply prevent other storage entries within Vault from being seal wrapped.

_N.B._: This is a lazy downgrade; as keys are accessed or written their seal
wrapping status will change. Similarly, if the flag is removed, it will be a
lazy upgrade (which is the case when initially upgrading to a seal
wrap-supporting version of Vault).

## Activating seal wrapping

For some values, seal wrapping is always enabled with a supporting seal. This
includes the recovery key, any stored key shares, the root key, the keyring,
and more; essentially, any Critical Security Parameter (CSP) within Vault's
core. If upgrading from a version of Vault that did not support seal wrapping,
the next time these values are read they will be seal-wrapped and stored.

Backend mounts within Vault can also take advantage of seal wrapping. Seal
wrapping can be activated at mount time for a given mount by mounting the
backend with the `seal_wrap` configuration value set to `true`. (This value
cannot currently be changed later.)

A given backend's author can specify which values should be seal-wrapped by
identifying where CSPs are stored.  They may also choose to seal wrap all or none
of their values.

Note that it is often an order of magnitude or two slower to write to and read
from HSMs or remote seals. However, values will be cached in memory
un-seal-wrapped (but still encrypted by Vault's built-in cryptographic barrier)
in Vault, which will mitigate this for read-heavy workloads.

## Seal wrap and replication

Seal wrapping takes place below the replication logic. As a result, it is
transparent to replication. Replication will convey which values should be
seal-wrapped, but it is up to the seal on the local cluster to implement it.
In practice, this means that seal wrapping can be used without needing to have
the replicated keys on both ends of the connection; each cluster can have
distinct keys in an HSM or in KMS.

In addition, it is possible to replicate from a Shamir-protected primary
cluster to clusters that use HSMs when seal wrapping is required in downstream
datacenters but not in the primary.

## Wrapped parameters

Each plugin (whether secret or auth) maintains control over parameters it
feels are best to Seal Wrap. These are usually just a few core values as
Seal Wrapping does incur some performance overhead.

Some examples of places where seal wrapping is used include:

- The [LDAP](/vault/docs/auth/ldap), [RADIUS](/vault/docs/auth/radius),
  [Okta](/vault/docs/auth/okta), and [AWS](/vault/docs/auth/aws) auth methods,
  for storing their config.
- [PKI](/vault/docs/secrets/pki) for storing the issuers and their keys,
- [SSH](/vault/docs/secrets/ssh) for storing the CA's keys,
- [KMIP](/vault/docs/secrets/kmip) for storing managed objects (externally-provided
  keys) and its CA keys.
- [Transit](/vault/docs/secrets/transit) for storing keys and their policy.

## FIPS status

See the [FIPS-specific Seal Wrap documentation](/vault/docs/enterprise/fips/sealwrap)
for more information about using Seal Wrapping to achieve FIPS 140-2 compliance.
Note that there are additional [FIPS considerations](/vault/docs/enterprise/sealwrap#seal-wrap-and-replication)
regarding Seal Wrap usage and Vault Replication.

[configuration]: /vault/docs/configuration
