Вы можете использовать метод ранжирования паролей:
<code>$x = "a12ASD!@#$";
$rank = Array();
$rank['length'] = strlen($x);
$matches = Array();
preg_match_all("/([a-z]+)/", $x, $matches);
$rank['lowercase'] = strlen(implode('', $matches[0]))/count($matches[0]);
$matches = Array();
preg_match_all("/([A-Z]+)/", $x, $matches);
$rank['uppercase'] = strlen(implode('', $matches[0]))/count($matches[0]);
$matches = Array();
preg_match_all("/([0-9]+)/", $x, $matches);
$rank['numbers'] = strlen(implode('', $matches[0]))/count($matches[0]);
$matches = Array();
preg_match_all("/([^a-zA-Z0-9]+)/", $x, $matches);
$rank['symbols'] = strlen(implode('', $matches[0]))/count($matches[0]);
echo "<pre>";
var_dump($rank);
echo "
";