Do we need both `CLOAK_KEYCHAIN` and `CLOAK_MASTER_KEY` or one of them

I'm integrating this extension and it's working great so far! It's simple to set up and it works transparently, I love it! 🙌

I'm curious if we need to provide both `CLOACK_KEYCHAIN` and `CLOAK_MASTER_KEY` to our environment when deploying the API.

When using the extension, I see only `CLOAK_MASTER_KEY` is documented, what to do with `CLOAK_KEYCHAIN`?

```ts
export const prisma = new PrismaClient().$extends(
fieldEncryptionExtension({
encryptionKey: process.env['CLOAK_MASTER_KEY'],
}),
)
```

Some clarity here would be highly appreciated.