Server-Side Object Encryption with Hashicorp Vault Root KMS

Deploy or Ensure Access to a Hashicorp Vault Service

This procedure assumes an existing Hashicorp Vault installation accessible from the local host. The Vault Quick Start provides a sufficient foundation for the purposes of this procedure. Defer to the Vault Documentation for guidance on deployment and configuration.

MinIO KES supports either the V1 or V2 Vault K/V engines.

MinIO KES requires using AppRole authentication to the Vault server. You must create an AppRole, assign it a policy that the necessary permissions, and retrieve the AppRole ID and Secret for use in configuring KES.

You can use the following steps to enable AppRole authentication and create the necessary policies to support core KES functionality against Vault:

1. Enable AppRole Authentication

   vault auth enable approle
   

2. Create a Policy for KES

   Create a policy with necessary capabilities for KES to use when accessing Vault. Select the tab corresponding to the KV engine used for storing KES secrets:

   Vault Engine V1

   Create an access policy kes-policy.hcl with a configuration similar to the following:

   path "kv/*" {
         capabilities = [ "create", "read", "delete" ]
   }
   

   Write the policy to Vault using vault policy write kes-policy kes-policy.hcl.

   Vault Engine V2

   Create an access policy kes-policy.hcl with a configuration similar to the following:

   path "kv/data/*" {
         capabilities = [ "create", "read"]
   }
   
   path "kv/metadata/*" {
         capabilities = [ "list", "delete"]
   }
   

   Write the policy to Vault using vault policy write kes-policy kes-policy.hcl

3. Create an AppRole for KES and assign it the created policy

   vault write    auth/approle/role/kes-role token_num_uses=0 secret_id_num_uses=0 period=5m
   vault write    auth/approle/role/kes-role policies=kes-policy
   

4. Retrieve the AppRole ID and Secret

   vault read     auth/approle/role/kes-role/role-id
   vault write -f auth/approle/role/kes-role/secret-id
   

Deploy or Ensure Access to a MinIO Deployment

This procedure provides instructions for modifying the startup environment variables of a MinIO deployment to enable SSE via KES and the root KMS.

For instructions on new production deployments, see the Multi-Node Multi-Drive (Distributed) tutorial. For instructions on new local or evaluation deployments, see the Single-Node Single-Drive tutorial.

When creating the environment file for the deployment, pause and switch back to this tutorial to include the necessary environment variables to support SSE.

For existing MinIO Deployments, you can modify the existing environment file and restart the deployment as instructed during this procedure.

1) Download KES and Create the Service File

2) Generate TLS Certificates for KES

KES requires TLS connectivity for all client connections, including those originating from MinIO. See Network Encryption (TLS) for more information on enabling TLS for the MinIO deployment.

Depending on your Vault configuration, you may also need to create a dedicated set of TLS certificates for KES to connect and authenticate to Vault.

Defer to your organization’s best practices around generating production-ready TLS certificates.

Place the certificates and corresponding private keys in a directory that the KES service user has permissions to access and read the directory’s contents. For example:

-rw-r--r-- 1 kes:kes /opt/kes/certs/kes-server.cert
-rw-r--r-- 1 kes:kes /opt/kes/certs/kes-server.key

# If the Vault certs are self-signed or use a non-global CA
# Include those CA certs as well

-rw-r--r-- 1 kes:kes /opt/kes/certs/vault-CA.cert

Depending on your Vault configuration, you may also need to specify the CA used to sign the KES certificates to the Vault server. See the Hashicorp Vault Configuration Docs for more information. Defer to the client documentation for instructions on trusting a third-party CA.

3) Generate a KES API Key for use by MinIO

Starting with KES version 2023-02-15T14-54-37Z, you can generate an API key to use for authenticating to the KES server.

Use the kes identity new command to generate a new API key for use by the MinIO Server:

kes identity new

The output includes both the API Key for use with MinIO and the Identity hash for use with the KES Policy configuration.

4) Create the KES and MinIO Configurations

5) Start KES and MinIO

You must start KES before starting MinIO. The MinIO deployment requires access to KES as part of its startup.

This step uses systemd for starting and managing both the KES and MinIO server processes:

1. Start the KES Service on All Hosts

   Run the following command on each KES host to start the service:

   systemctl start kes
   

   You can validate the startup by using systemctl status kes. If the service started successfully, use journalctl -uf kes to check the KES output logs.

2. Start the MinIO Server

   For new MinIO deployments, run the following command on each MinIO host to start the service:

   systemctl start minio
   

   For existing MinIO deployments, run the following command on each MinIO host to restart the service:

   systemctl reload minio
   systemctl restart minio
   

5) Generate a New Encryption Key

MinIO requires that the EK exist on the root KMS before performing SSE operations using that key. Use kes key create or mc admin kms key create to add a new EK for use with SSE.

The following command uses the mc admin kms key create command to add a new External Key (EK) stored on the root KMS server for use with encrypting the MinIO backend.

mc admin kms key create ALIAS KEYNAME

6) Enable SSE-KMS for a Bucket

You can use either the MinIO Console or the MinIO mc CLI to enable bucket-default SSE-KMS with the generated key:

mc alias set local http://127.0.0.1:9000 ROOTUSER ROOTPASSWORD

mc mb local/encryptedbucket
mc encrypt set SSE-KMS encrypted-bucket-key ALIAS/encryptedbucket