function valide_motdepasse($chaine, $mode = 2){
	$minimum = array(1 => 4, 2 => 6, 3 => 8);
	$pourcentage = array(1 => 26, 2 => 51, 3 => 76);
	if(preg_match('#[a-z-0-9]{'.$minimum[$mode].',}#', $chaine)){
		$a_chaine = str_split($chaine);
		$c_uniques = array_unique($a_chaine);
		if(count($c_uniques)*100/count($a_chaine) >= $pourcentage[$mode]){
			return true;
		}
	}
	return false;
}
?>