2019-10-28 22:04:27 +00:00
---
2020-01-18 00:18:09 +00:00
layout: docs
page_title: Entropy Augmentation - Configuration
description: >-
Entropy augmentation enables Vault to sample entropy from external
cryptographic modules.
2019-10-28 22:04:27 +00:00
---
# `Entropy Augmentation` Seal
2020-03-31 19:21:16 +00:00
Entropy augmentation enables Vault to sample entropy from external cryptographic modules.
2023-01-26 00:12:15 +00:00
Sourcing external entropy is done by configuring a supported [Seal](/vault/docs/configuration/seal) type which
include: [PKCS11 seal](/vault/docs/configuration/seal/pkcs11), [AWS KMS](/vault/docs/configuration/seal/awskms), and
[Vault Transit](/vault/docs/configuration/seal/transit).
2020-01-18 00:18:09 +00:00
Vault Enterprises's external entropy support is activated by the presence of an `entropy "seal"`
block in Vault's configuration file.
2019-10-28 22:04:27 +00:00
## Requirements
2022-06-07 15:23:26 +00:00
A valid Vault Enterprise license is required for Entropy Augmentation.
~> **Warning** This feature is not available with FIPS 140-2 Inside variants of Vault.
2019-10-28 22:04:27 +00:00
2020-01-21 23:05:53 +00:00
Additionally, the following software packages and enterprise modules are required for sourcing entropy
2023-01-26 00:12:15 +00:00
via the [PKCS11 seal](/vault/docs/configuration/seal/pkcs11):
2020-03-31 19:21:16 +00:00
2021-09-08 15:59:25 +00:00
- Vault Enterprise with the Plus package
2019-10-28 22:04:27 +00:00
- PKCS#11 compatible HSM integration library. Vault targets version 2.2 or
higher of PKCS#11. Depending on any given HSM, some functions (such as key
generation) may have to be performed manually.
2020-01-21 23:05:53 +00:00
- The [GNU libltdl library](https://www.gnu.org/software/libtool/manual/html_node/Using-libltdl)
2019-10-28 22:04:27 +00:00
— ensure that it is installed for the correct architecture of your servers
2020-01-21 23:05:53 +00:00
2019-10-28 22:04:27 +00:00
## `entropy` Example
This example shows configuring entropy augmentation through a PKCS11 HSM seal from Vault's configuration
file:
```hcl
seal "pkcs11" {
...
}
entropy "seal" {
mode = "augmentation"
}
```
2023-02-07 04:34:51 +00:00
For a more detailed tutorial, visit the [HSM Entropy Challenge](/vault/tutorials/enterprise/hsm-entropy)
2020-01-21 23:05:53 +00:00
on HashiCorp's Learn website.
2019-10-28 22:04:27 +00:00
## `entropy augmentation` Parameters
These parameters apply to the `entropy` stanza in the Vault configuration file:
- `mode` `(string: <required>)`: The mode determines which Vault operations requiring
2020-01-18 00:18:09 +00:00
entropy will sample entropy from the external source. Currently, the only mode supported
2023-01-26 00:12:15 +00:00
is `augmentation` which sources entropy for [Critical Security Parameters (CSPs)](/vault/docs/enterprise/entropy-augmentation#critical-security-parameters-csps).
