public static function verify_password($pass1, $pass2) {
		$pass1 = trim($pass1);
		$pass2 = trim($pass2);
		# type twice the same
		if ($pass1 != $pass2)
			return AdminStoreError::PASSWORD_NOT_SAME;
		# must be longer than 3
		if (strlen($pass1) < 4)
			return AdminStoreError::PASSWORD_TOO_SHORT;
		return 0;
	}