I have never really done any serious web programming, other than just a blog or a static web page. For a web application I am developing though, I need to have web site logins.
In an attempt to not reinvent the wheel, how can I implement logins? Is there a "drop-in" component somewhere? I'm not averse to fooling around with cryptography, but I don't really have much experience using PHP or web protocols.
EDIT: I am using the CodeIgniter framework, so if anyone has any answers in that context, I'd be interested.