Simplest, smallest PHP account system

There's an interesting example 开发者_开发百科of someone managing to create a PHP script for a forum which only takes up 1kb: http://www.nerdparadise.com/blogs/blake/6034/

I wonder if there a similar tiny script(s) which could handle user accounts (and could perhaps be added to the above forum script). I'm thinking each account would hold just a username, email and password.

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Magic quotes need to be enabled to prevent SQL injection!

LOL, don't even think of using this.