public function is_valid($password, $check_rehash=true) {
	if (password_verify($password, $this->data['hash']) == false) {
		return false;
	}
	
	if ($check_rehash && password_needs_rehash($this->data['hash'], PASSWORD_DEFAULT)) {
		$new_hash = self::hash_password($password);
		$this->set_new_hash($this->data['user_id'], $this->data['email_address'], $new_hash);
	}
	
	return true;
}