Server-Side Object Encryption with KES

Kubernetes

This procedure assumes you have access to a Kubernetes cluster with an active MinIO Operator installation. For instructions on running KES, see the KES docs.

As part of this procedure, you will:

Create or modify a MinIO deployment with support for SSE using KES. Defer to the Deploy Distributed MinIO tutorial for guidance on production-ready MinIO deployments.
Use the MinIO Operator Console to create or manage a MinIO Tenant.
Access the Encryption settings for that tenant and configure SSE using a supported Key Management System.
Create a new EK for use with SSE.
Configure automatic bucket-default SSE-KMS.

Baremetal

This procedure provides guidance for deploying MinIO configured to use KES and enable Server Side Encryption. For instructions on running KES, see the KES docs.

As part of this procedure, you will:

Create a new EK for use with SSE.
Create or modify a MinIO deployment with support for SSE using KES. Defer to the Deploy Distributed MinIO tutorial for guidance on production-ready MinIO deployments.
Configure automatic bucket-default SSE-KMS

Important

Enabling SSE on a MinIO deployment automatically encrypts the backend data for that deployment using the default encryption key.

MinIO requires access to KES and the external KMS to decrypt the backend and start normally. The KMS must maintain and provide access to the MINIO_KMS_KES_KEY_NAME. You cannot disable KES later or “undo” the SSE configuration at a later point.

Prerequisites

Access to MinIO Cluster

Ensure KES Access to a Supported KMS Target

KES Operations Require Unsealed Target

Some supported KMS targets allow you to seal or unseal the vault instance. KES returns an error if the configured KMS service is sealed.

If you restart or otherwise seal your vault instance, KES cannot perform any cryptographic operations against the vault. You must unseal the Vault to ensure normal operations.

See the documentation for your chosen KMS solution for more information on whether unsealing may be required.

Refer to the configuration instruction in the KES documentation for your chosen supported KMS:

Procedure

This procedure provides instructions for configuring and enabling Server-Side Encryption using your selected supported KMS solution in production environments. Specifically, this procedure assumes the following:

An existing production-grade KMS target
One or more KES servers connected to the KMS target
One or more hosts for a new or existing MinIO deployment

Kubernetes

Review the Tenant CRD

Review the Tenant CRD TenantSpec.kes object, the TenantSpec.configuration object, and the KES Configuration reference.

You must prepare all necessary configurations associated to your external Key Management Service of choice before proceeding.
Create or Modify your Tenant YAML to set the values of KesConfig as necessary:

You must modify your Tenant YAML or Kustomize templates to reflect the necessary KES configuration. The following example is taken from the MinIO Operator Kustomize examples
```
kes:
   image: "" # minio/kes:2024-06-17T15-47-05Z
   env: [ ]
   replicas: 2
   kesSecret:
      name: kes-configuration
   imagePullPolicy: "IfNotPresent"
```
The kes-configuration secret must reference a Kubernetes Opaque Secret which contains a stringData object with the full KES configuration as server-config.yaml. The keystore field must contain the full configuration associated with your preferred Key Management System.

Reference the Kustomize example for additional guidance.
Create or Modify your Tenant YAML to set the values of TenantSpec.configuration as necessary.

TODO
Generate a New Encryption Key

Unseal Vault Before Creating Key

If required by your chosen provider, you must unseal the backing vault instance before creating new encryption keys. See the documentation for your chosen KMS solution for more information.

MinIO requires that the EK for a given bucket or object exist on the root KMS before performing SSE operations using that key. You can use the mc admin kms key create command against the MinIO Tenant.

You must ensure your local host can access the MinIO Tenant pods and services before using mc to manage the Tenant. For hosts internal to the Kubernetes cluster, you can use the service DNS name. For hosts external to the Kubernetes cluster, specify the hostname of the service exposed by Ingress, Load Balancer, or similar Kubernetes network control component.

Run this command in a separate Terminal or Shell:
```
# Replace '-n minio' with the namespace of the MinIO deployment
# If you deployed the Tenant without TLS you may need to change the port range

# You can validate the ports in use by running
#  kubectl get svc/minio -n minio

kubectl port forward svc/minio 443:443 -n minio
```
The following commands in a new Terminal or Shell window:
- Connect a local mc client to the Tenant.
- Create the encryption key.
See Quickstart for instructions on installing mc on your local host.
```
# Replace USERNAME and PASSWORD with a user on the tenant with administrative permissions
# such as the root user

mc alias add k8s https://localhost:443 ROOTUSER ROOTPASSWORD

# Replace my-new-key with the name of the key you want to use for SSE-KMS
mc admin kms key create k8s encrypted-bucket-key
```
Enable SSE-KMS for a Bucket

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

Connect to the MinIO Tenant Console service and log in. For clients internal to the Kubernetes cluster, you can specify the service DNS name. For clients external to the Kubernetes cluster, specify the hostname of the service exposed by Ingress, Load Balancer, or similar Kubernetes network control component.

Once logged in, create a new Bucket and name it to your preference. Select the Gear icon to open the management view.

Select the pencil icon next to the Encryption field to open the modal for configuring a bucket default SSE scheme.

Select SSE-KMS, then enter the name of the key created in the previous step.

Once you save your changes, try to upload a file to the bucket. When viewing that file in the object browser, note that in the sidebar the metadata includes the SSE encryption scheme and information on the key used to encrypt that object. This indicates the successful encrypted state of the object.

MinIO CLI
Use the MinIO API Service to create a new alias for the MinIO deployment. You can then use the mc encrypt set command to enable SSE-KMS encryption for a bucket:
mc alias set k8s https://minio.minio-tenant-1.svc.cluster-domain.example:443 ROOTUSER ROOTPASSWORD mc mb k8s/encryptedbucket mc encrypt set SSE-KMS encrypted-bucket-key k8s/encryptedbucket
For clients external to the Kubernetes cluster, specify the hostname of the service exposed by Ingress, Load Balancer, or similar Kubernetes network control component.

Write a file to the bucket using mc cp or any S3-compatible SDK with a PutObject function. You can then run mc stat on the file to confirm the associated encryption metadata.

Baremetal

Generate a KES API Key for use by MinIO

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.
Configure the MinIO Environment File

Create or modify the MinIO Server environment file for all hosts in the target deployment to include the following environment variables:

Add the following lines to the MinIO Environment file on each MinIO host. See the tutorials for Install MinIO Object Storage, Install MinIO Object Storage, or Install MinIO Object Storage for more detailed descriptions of a base MinIO environment file.
```
# Add these environment variables to the existing environment file

MINIO_KMS_KES_ENDPOINT=https://HOSTNAME:7373
MINIO_KMS_KES_API_KEY="kes:v1:ACTpAsNoaGf2Ow9o5gU8OmcaG6Af/VcZ1Mt7ysuKoBjv"

# Allows validation of the KES Server Certificate (Self-Signed or Third-Party CA)
# Change this path to the location of the KES CA Path
MINIO_KMS_KES_CAPATH=|kescertpath|/kes-server.cert

# Sets the default KMS key for the backend and SSE-KMS/SSE-S3 Operations)
MINIO_KMS_KES_KEY_NAME=minio-backend-default-key
```
Replace HOSTNAME with the IP address or hostname of the KES server. If the MinIO server host machines cannot resolve or reach the specified HOSTNAME, the deployment may return errors or fail to start.
- If using a single KES server host, specify the IP or hostname of that host
- If using multiple KES server hosts, specify a comma-separated list of IPs or hostnames of each host
MinIO uses the MINIO_KMS_KES_KEY_NAME key for the following cryptographic operations:
- Encrypting the MinIO backend (IAM, configuration, etc.)
- Encrypting objects using SSE-KMS if the request does not include a specific EK.
- Encrypting objects using SSE-S3.
MinIO defaults to expecting this file at /etc/default/minio. If you modified your deployment to use a different location for the environment file, modify the file at that location.
Start MinIO

KES Operations Requires Unsealed Vault

Depending on your selected KMS solution, you may need to unseal the key instance to allow normal cryptographic operations, including key creation or retrieval. KES requires an unsealed key target to perform its operations.

Refer to the documentation for your chosen KMS solution for information regarding whether sealing and unsealing the instance is required for operations.

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

You can use the mc admin service restart command to restart MinIO:
```
mc admin service restart ALIAS
```
Generate a New Encryption Key

MinIO requires that the EK exist on the 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 KMS server for use with encrypting the MinIO backend.
```
mc admin kms key create ALIAS KEYNAME
```
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:
MinIO Console

Open the MinIO Console by navigating to http://127.0.0.1:9001 in your preferred browser and logging in with the root credentials specified to the MinIO Server. If you deployed MinIO using a different Console listen port, substitute 9001 with that port value.

Once logged in, create a new Bucket and name it to your preference. Select the Gear icon to open the management view.

Select the pencil icon next to the Encryption field to open the modal for configuring a bucket default SSE scheme.

Select SSE-KMS, then enter the name of the key created in the previous step.

Once you save your changes, try to upload a file to the bucket. When viewing that file in the object browser, note that the sidebar metadata includes the SSE encryption scheme and information on the key used to encrypt that object. This indicates the successful encrypted state of the object.

MinIO CLI
The following commands:
- Create a new alias for the MinIO deployment
- Create a new bucket for storing encrypted data
- Enable SSE-KMS encryption on that bucket
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
Write a file to the bucket using mc cp or any S3-compatible SDK with a PutObject function. You can then run mc stat on the file to confirm the associated encryption metadata.