Auth Class: Manage accounts and authenticate users

User Authentication PHP Class
=============================

This is a simple user authentication class for PHP, which uses
a MySQL Database which is accessed via MySQLi.

The system also includes a Custom user session system, meaning
sessions can last a predefined time, for example, 1 minute to over 10 years
if that was ever needed.

The Current functions are as follows :

- login($username, $password) : Verifies user credentials
- register($username, $password, $verifypassword, $email) : Adds a new user account to the database
- newsession($username) : Creates a new session for the user
- deletesession($hash) : Deletes an existing session from the database, and removes the user's cookie
- sessioninfo($hash) : Retrieves info about the session from database (UID, Username, Expire Date, IP)
- checksession($hash) : Checks if session is valid
- randomkey($length) : Returns a random key, used as activation key, contain lowercase / uppercase letters and numbers
- activate($username, $key) : Activates an account based on username and activation key
- changepass($username, $currpass, $newpass, $verifynewpass) : Changes the user's password. Requires current password
- changeemail($username, $email) : Changes the user's email
- resetpass($username, $email, $key, $newpass, $verifynewpass) : Sends reset request email and resets user's password
- checkresetkey($username, $key) : Checks the reset key based on username, returns true / false
- deleteaccount($username, $password) : Deletes the user's account. Requires current password
- addattempt($ip) : Logs a new attempt of authentication based on user IP
- getattempt($ip) : Retrieves amount of attempts from database based on user IP
- expireattempt() : Removes expired attempt logs from database, should be ran as cron job
- LogActivity($username, $action, $additionalinfo) : Logs the user's usage of the class, from login to logout. Includes attempts.
- hashpassword($password) : Hashes the password with the following : hash("SHA512", base64_encode(str_rot13(hash("SHA512", str_rot13($auth_conf['salt_1'] . $password . $auth_conf['salt_2'])))))

The extended encryption will result in a pratically uncrackable password. The session
system relies on the user's IP, if it changes, the user will have to reauthenticate.

Database layout is stored in auth.sql which you can import easily with PhpMyAdmin

Auth configuration is done in config.php where you can configure the MySQL database settings, attempts settings, email settings etc...