Generate random passwords that are highly secure

php-secure-password.php

<?php
/**
 *  Generate random passwords that are highly secure
 *
 * @return string
 * @param $level 1:easy 2:Normal 3:Hard
 * @author 
 **/
function generatePassword($length = 6, $level = 2){
	list($usec, $sec) = explode(' ', microtime());
	srand((float) $sec + ((float) $usec * 100000));

	$validchars[1] = '0123456789abcdfghjkmnpqrstvwxyz';
	$validchars[2] = '0123456789abcdfghjkmnpqrstvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
	$validchars[3] = '0123456789_!@#$%&*()-=+/abcdfghjkmnpqrstvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_!@#$%&*()-=+/';

	$password  = '';
	$counter   = 0;

	while ($counter < $length) {
		$actChar = substr($validchars[$level], rand(0, strlen($validchars[$level])-1), 1);
		// All character must be different
		if (!strstr($password, $actChar)) {
			$password .= $actChar;
			$counter++;
		}
	}
	return $password;
}
?>