/**
 * @file dh.h
 * @brief Diffie-Hellman key exchange
 *
 * @section License
 *
 * Copyright (C) 2010-2014 Oryx Embedded. All rights reserved.
 *
 * This file is part of CycloneCrypto Open.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * @author Oryx Embedded (www.oryx-embedded.com)
 * @version 1.4.4
 **/

#ifndef _DH_H
#define _DH_H

//Dependencies
#include "crypto.h"
#include "mpi.h"


/**
 * @brief Diffie-Hellman parameters
 **/

typedef struct
{
   Mpi p; ///<Prime modulus
   Mpi g; ///<Generator
} DhParameters;


/**
 * @brief Diffie-Hellman context
 **/

typedef struct
{
   DhParameters params; //Diffie-Hellman parameters
   Mpi xa;              ///<One's own private value
   Mpi ya;              ///<One's own public value
   Mpi yb;              ///<Peer's public value
} DhContext;


//Diffie-Hellman related functions
void dhInit(DhContext *context);
void dhFree(DhContext *context);

error_t dhGenerateKeyPair(DhContext *context,
   const PrngAlgo *prngAlgo, void *prngContext);

error_t dhCheckPublicKey(DhParameters *params, const Mpi *publicKey);

error_t dhComputeSharedSecret(DhContext *context,
   uint8_t *output, size_t outputSize, size_t *outputLength);

#endif
