Web App Installer V2.1 Password security

<?php
/*
Auto Web Application Download/Install Script!

Version 2.1
Copyright 2014 All Rights Reserved Enkel Hosting Ltd

More PHP Scrips at http://devbox.enkelhosting.com

*/

//      Options
$security = 'none'; //Security method

/*

Security Modes:

ip: Use a whitelist IP and only allow access to someone on that IP
password: User will be asked to enter the password chosen
none: No security will be used

*/


//      IP Whitelist Options
$ip = '000.000.000.000'; //Remote IP


//      Password Options
$password = 'Password123';

$debug = false;

if( $security == 'ip' ){
    if( $ip != $_SERVER['REMOTE_ADDR'] ){
        echo 'Your IP is not whitelisted!';
        exit;
    }
} else if( $security == 'password' && !isset($_GET['password'] ) ){
    echo 'Please type the password!';
    echo '<form>';
    echo '<input type="password" name="password">';
    echo '<input type="submit" value="Login">';
    echo '</form>';
    exit;
} else if( $security == 'password' && isset($_GET['password'] ) ){
    if( $password != $_GET['password'] ){
        echo 'Incorrect Password';
        exit;
    }
} else if( $security == 'none' ){

} else {
    echo 'Invalid Security Mode';
    exit;
}