/*
     This file is part of GNUnet.
     Copyright (C) 2013, 2014 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file scalarproduct/gnunet-service-scalarproduct.h
 * @brief scalarproduct service  P2P messages
 * @author Christian M. Fuchs
 * @author Christian Grothoff
 */
#ifndef GNUNET_SERVICE_SCALARPRODUCT_H
#define GNUNET_SERVICE_SCALARPRODUCT_H


GNUNET_NETWORK_STRUCT_BEGIN

/**
 * Message type passed from requesting service Alice to responding
 * service Bob to initiate a request and make Bob participate in our
 * protocol.  Afterwards, Bob is expected to perform the set
 * intersection with Alice. Once that has succeeded, Alice will
 * send a `struct AliceCryptodataMessage *`.  Bob is not expected
 * to respond via CADET in the meantime.
 */
struct ServiceRequestMessage
{
  /**
   * Type is #GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SESSION_INITIALIZATION
   */
  struct GNUNET_MessageHeader header;

  /**
   * For alignment. Always zero.
   */
  uint32_t reserved;

  /**
   * The transaction/session key used to identify a session
   */
  struct GNUNET_HashCode session_id;

  /**
   * Alice's public key
   */
  struct GNUNET_CRYPTO_PaillierPublicKey public_key;
};


/**
 * Vector of Pallier-encrypted values sent by Alice to Bob
 * (after set intersection).  Alice may send messages of this
 * type repeatedly to transmit all values.
 */
struct AliceCryptodataMessage
{
  /**
   * Type is #GNUNET_MESSAGE_TYPE_SCALARPRODUCT_ALICE_CRYPTODATA
   */
  struct GNUNET_MessageHeader header;

  /**
   * How many elements we appended to this message? In NBO.
   */
  uint32_t contained_element_count GNUNET_PACKED;

  /**
   * struct GNUNET_CRYPTO_PaillierCiphertext[contained_element_count]
   */
};


/**
 * Message type passed from responding service Bob to responding
 * service Alice to complete a request and allow Alice to compute the
 * result.  If Bob's reply does not fit into this one message, the
 * conversation may be continued with `struct BobCryptodataMultipartMessage`
 * messages afterwards.
 */
struct BobCryptodataMessage
{
  /**
   * GNUNET message header with type
   * #GNUNET_MESSAGE_TYPE_SCALARPRODUCT_BOB_CRYPTODATA.
   */
  struct GNUNET_MessageHeader header;

  /**
   * How many elements this individual message delivers (in NBO).
   */
  uint32_t contained_element_count GNUNET_PACKED;

  /**
   * followed by s | s' | k[i][perm]
   */
};


/**
 * Multipart Message type passed between to supply additional elements
 * for the peer.  Send from Bob to Alice with additional elements
 * of k[i][perm] after his `struct BobCryptodataMessage *`.
 * Once all k-values have been transmitted, Bob is finished and
 * Alice can transmit the final result to the client.
 */
struct BobCryptodataMultipartMessage
{
  /**
   * GNUNET message header
   */
  struct GNUNET_MessageHeader header;

  /**
   * How many elements we supply within this message? In NBO.
   */
  uint32_t contained_element_count GNUNET_PACKED;

  /**
   * Followed by `struct
   * GNUNET_CRYPTO_PaillierCiphertext[contained_element_count]`
   */
};


GNUNET_NETWORK_STRUCT_END


#endif
