Authentication against berkshelf source endpoint?

I want to setup my own supermarket for my own private cookbooks on the open Internet. I’d like access to these cookbooks to be secured. However, I don’t see how to specify authentication in the Berksfile to access this private source endpoint. Is there a way to do this? Or are berkshelf source endpoints meant to be unauthenticated at the moment?

Furthermore, how do you make knife supermarket share work in this case?

I know that the supermarket app supports OAuth (oc-id) authentication, but this is for the web ui only, right? Or is there a way to specify OAuth credentials for knife supermarket and berkshelf source usage?