The PHP Login Project has reached End of Life
Long story short: Back in 2010 it was nearly impossible to find a secure login script written in PHP, nearly all tutorials were doing it wrong, even most frameworks and the most used
PHP scripts were using totally outdated and insecure MD5 password hashing, and for sure some of the biggest companies in the world had no clue how to handle passwords properly
(looking at you, LinkedIn, SONY and Adobe). Security was no major topic.
And for less-experienced developers and beginners it was even harder. So I started this open-source project, collectively trying to write some login scripts in pure PHP for typicals use cases, doing it in the right way.
Now, in 2015, we have excellent frameworks with native user authentication features ("login systems") in the PHP world, widespread PHP 5.5 support, well-written tutorials and StackOverflow is there to help you in basically any situation. Creating a PHP application with all the wonderful features has become so much easier and so much less painless than years ago, so it's time to end this project and encourage users to use the really good and well maintained frameworks rather than trying to build everything from scratch. If you want to build beautiful applications with typical register / login / logout - features, then I strongly recommend you having a look at Laravel, Yii2 and Symfony.
The scripts below are not maintained anymore but will for sure stay online on GitHub. For quick and simple projects they might still be useful for you. If you like, also have a look at HUGE, a very simple framework with a fully integrated user authentication solution (that's my new project).
These ones still work fine, but are not maintained anymore
Full login script in one file (!) plus a one-file SQLite database (no MySQL needed) and PDO. Features: Register, login, logout.
All the basic functions in a clean file structure, uses MySQL and mysqli. Features: Register, login, logout.
Similar to the minimal version, but full of features. Uses PDO, password-reset, cookies, captcha, mail sending via SMTP and much more.
professional mvc version
Naked MVC application, URL rewriting, Facebook-login, PDO, Composer, PHPMailer, avatars, account upgrade/downgrade and much more. Stopped with v2.x in 2014, completely rewritten and renamed to HUGE.