/** ID of the key used for encryption/decryption, if there is one */
boost::optional<std::string> _key_id;
/** Key used for encryption/decryption, if there is one */
boost::optional<Key> _key;
/** ID of the key used for encryption/decryption, if there is one */
boost::optional<std::string> _key_id;
/** Key used for encryption/decryption, if there is one */
boost::optional<Key> _key;