Generator for randomic passwords

PasswordGenerator.php

<?php
class PasswordGenerator{
    
    /**
    * @param  integer  $length
    * @return string   $pass
    * @author Flávio Henrique Ferreira <flaviometalvale@gmail.com>
    **/    
    static function randomPassword($length = 8)
    {
        $alphabet = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789#!@$%";
        $password = array();
        $alphaLength = strlen($alphabet) - 1;
        for ($i = 0; $i < $length; $i++) 
        {
            $n = rand(0, $alphaLength);
            $password[] = $alphabet[$n];
        }
        /*
        * turn the array into a string
        */
        return implode($password); 
    }  
}
/*Usage*/
$pass = PasswordGenerator::randomPassword(24); //24 characters
$pass = PasswordGenerator::randomPassword(); //8 characters