public function remove(string $key)
  {
    $file = $this->file;

    if (file_exists($file)) {
      $data = unserialize($this->decrypt(file_get_contents($file)));

      if (is_array($data) && isset($data[$key])) {
        unset($data[$key]);
        $data = $this->encrypt(serialize($data));
        return file_put_contents($file, $data);
      }
    }

    return false;
  }