minio/docs/kms

KMS Guide

MinIO uses a key-management-system (KMS) to support SSE-S3. If a client requests SSE-S3, or auto-encryption is enabled, the MinIO server encrypts each object with an unique object key which is protected by a master key managed by the KMS.

Quick Start

MinIO supports multiple KMS implementations via our KES project. We run a KES instance at https://play.min.io:7373 for you to experiment and quickly get started. To run MinIO with a KMS just fetch the root identity, set the following environment variables and then start your MinIO server. If you havn't installed MinIO, yet, then follow the MinIO install instructions first.

1. As initial step fetch the private key and certificate of the root identity:

   curl -sSL --tlsv1.2 \
        -O 'https://raw.githubusercontent.com/minio/kes/master/root.key' \
        -O 'https://raw.githubusercontent.com/minio/kes/master/root.cert'
   

2. Set the MinIO-KES related environment variables:

   export MINIO_KMS_KES_ENDPOINT=https://play.min.io:7373
   export MINIO_KMS_KES_KEY_FILE=root.key
   export MINIO_KMS_KES_CERT_FILE=root.cert
   export MINIO_KMS_KES_KEY_NAME=my-minio-key
   

3. Start the MinIO server:

   export MINIO_ACCESS_KEY=minio
   export MINIO_SECRET_KEY=minio123
   minio server ~/export
   

The KES instance at https://play.min.io:7373 is meant to experiment and provides a way to get started quickly. Note that anyone can access or delete master keys at https://play.min.io:7373. You should run your own KES instance in production.

Configuration Guides

A typical MinIO deployment that uses a KMS for SSE-S3 looks like this:

    ┌────────────┐
    │ ┌──────────┴─┬─────╮          ┌────────────┐
    └─┤ ┌──────────┴─┬───┴──────────┤ ┌──────────┴─┬─────────────────╮
      └─┤ ┌──────────┴─┬─────┬──────┴─┤ KES Server ├─────────────────┤
        └─┤   MinIO    ├─────╯        └────────────┘            ┌────┴────┐
          └────────────┘                                        │   KMS   │
                                                                └─────────┘

So, there are n MinIO instances talking to m KES servers but only 1 central KMS. The most simple setup consists of 1 MinIO server or cluster talking to 1 KMS via 1 KES server.

The main difference between various MinIO-KMS deployments is the KMS implementation. The following table helps you select the right option for your use case:

KMS	Purpose
Hashicorp Vault	Local KMS. MinIO and KMS on-prem (Recommended)
AWS-KMS + SecretsManager	Cloud KMS. MinIO in combination with a managed KMS installation
FS	Local testing or development (Not recommended for production)

The MinIO-KES configuration is always the same - regardless of the underlying KMS implementation. Checkout the MinIO-KES configuration example.

Further references

• Run MinIO with TLS / HTTPS
• Tweak the KES server configuration
• Run a load balancer infront of KES
• Understand the KES server concepts

Auto Encryption

Optionally, you can instruct the MinIO server to automatically encrypt all objects with keys from the KES server - even if the client does not specify any encryption headers during the S3 PUT operation.

Auto-Encryption is especially useful when the MinIO operator wants to ensure that all data stored on MinIO gets encrypted before it's written to the storage backend.

To enable auto-encryption set the environment variable to on:

export MINIO_KMS_AUTO_ENCRYPTION=on

Note that auto-encryption only affects requests without S3 encryption headers. So, if a S3 client sends e.g. SSE-C headers, MinIO will encrypt the object with the key sent by the client and won't reach out to the KMS.

To verify auto-encryption, use the mc command:

mc cp test.file myminio/bucket/
test.file:              5 B / 5 B  ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  100.00% 337 B/s 0s

mc stat myminio/bucket/test.file
Name      : test.file
...
Encrypted :
  X-Amz-Server-Side-Encryption: AES256

Explore Further

• Use mc with MinIO Server
• Use aws-cli with MinIO Server
• Use s3cmd with MinIO Server
• Use minio-go SDK with MinIO Server
• The MinIO documentation website