Instead of configuring an external KMS you can start with a single key by
setting the env. variable `MINIO_KMS_SECRET_KEY`. It expects the following
format:

```sh
MINIO_KMS_SECRET_KEY=<key-name>:<base64-value>
```

First generate a 256 bit random key via:

```sh
$ cat /dev/urandom | head -c 32 | base64 -
OSMM+vkKUTCvQs9YL/CVMIMt43HFhkUpqJxTmGl6rYw=
```

Now, you can set `MINIO_KMS_SECRET_KEY` like this:

```sh