contraseña de Regex PHP
^(?=\P{Ll}*\p{Ll})(?=\P{Lu}*\p{Lu})(?=\P{N}*\p{N})(?=[\p{L}\p{N}]*[^\p{L}\p{N}])[\s\S]{8,}$
Fierce Fox
^(?=\P{Ll}*\p{Ll})(?=\P{Lu}*\p{Lu})(?=\P{N}*\p{N})(?=[\p{L}\p{N}]*[^\p{L}\p{N}])[\s\S]{8,}$
if(preg_match((?=^.{8,}$)((?=.*\d)|(?=.*\W+))(?![.\n])(?=.*[A-Z])(?=.*[a-z]).*$, $_POST['password']):
echo 'matched';
else:
echo 'not matched';
endif;