Creating your own authentication system

I a looking to create a user authentication system on my own (using Rails 3) since I do not need开发者_如何学编程 all the features that for example authlogic or Device is offering, no matter how great they are. I am going to use the system for handling user authentication as an API that my iPhone app is going to use.

These are my simple requirements.

1. Basic email/password
2. Token based authentication from the iPhone app.

Could someone point out a great guide or blog post discussing this or simular so that I can get started and make sure I do not miss vital security issues.

Thanks!

---

Check out Railscast #250: Authentication from Scratch. Should cover what you need it to.