Would love to see your angular demo implement authentication.
Also, your angular demo uses angularfire.js.
I've been reading the docs and questions like these are not readily accessible.
You can also observe arbitrary data changes and log any info that is relevant to you.
As for passwords, we have a few details here at the bottom of the page here: https://www.firebase.com/docs/security-quickstart.html
The short answer is that we use bcrypt for password storage.
Hope that helps!
You can also use the REST API (https://www.firebase.com/docs/rest-api-quickstart.html) to interact with Firebase from any platform.