blob: 52b0bf94a3f04afd750e9c9419fab335a72953fd [file] [log] [blame] [raw]
/**
* \file dhm.h
*
* \brief Diffie-Hellman-Merkle key exchange
*
* Copyright (C) 2006-2010, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* 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.
*/
#ifndef POLARSSL_DHM_H
#define POLARSSL_DHM_H
#include "bignum.h"
/*
* DHM Error codes
*/
#define POLARSSL_ERR_DHM_BAD_INPUT_DATA -0x3080 /**< Bad input parameters to function. */
#define POLARSSL_ERR_DHM_READ_PARAMS_FAILED -0x3100 /**< Reading of the DHM parameters failed. */
#define POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED -0x3180 /**< Making of the DHM parameters failed. */
#define POLARSSL_ERR_DHM_READ_PUBLIC_FAILED -0x3200 /**< Reading of the public values failed. */
#define POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED -0x3280 /**< Makeing of the public value failed. */
#define POLARSSL_ERR_DHM_CALC_SECRET_FAILED -0x3300 /**< Calculation of the DHM secret failed. */
/**
* \brief DHM context structure
*/
typedef struct
{
size_t len; /*!< size(P) in chars */
mpi P; /*!< prime modulus */
mpi G; /*!< generator */
mpi X; /*!< secret value */
mpi GX; /*!< self = G^X mod P */
mpi GY; /*!< peer = G^Y mod P */
mpi K; /*!< key = GY^X mod P */
mpi RP; /*!< cached R^2 mod P */
}
dhm_context;
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief Parse the ServerKeyExchange parameters
*
* \param ctx DHM context
* \param p &(start of input buffer)
* \param end end of buffer
*
* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
*/
int dhm_read_params( dhm_context *ctx,
unsigned char **p,
const unsigned char *end );
/**
* \brief Setup and write the ServerKeyExchange parameters
*
* \param ctx DHM context
* \param x_size private value size in bytes
* \param output destination buffer
* \param olen number of chars written
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \note This function assumes that ctx->P and ctx->G
* have already been properly set (for example
* using mpi_read_string or mpi_read_binary).
*
* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
*/
int dhm_make_params( dhm_context *ctx, int x_size,
unsigned char *output, size_t *olen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
* \brief Import the peer's public value G^Y
*
* \param ctx DHM context
* \param input input buffer
* \param ilen size of buffer
*
* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
*/
int dhm_read_public( dhm_context *ctx,
const unsigned char *input, size_t ilen );
/**
* \brief Create own private value X and export G^X
*
* \param ctx DHM context
* \param x_size private value size in bits
* \param output destination buffer
* \param olen must be equal to ctx->P.len
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
*/
int dhm_make_public( dhm_context *ctx, int x_size,
unsigned char *output, size_t olen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
* \brief Derive and export the shared secret (G^Y)^X mod P
*
* \param ctx DHM context
* \param output destination buffer
* \param olen number of chars written
*
* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
*/
int dhm_calc_secret( dhm_context *ctx,
unsigned char *output, size_t *olen );
/*
* \brief Free the components of a DHM key
*/
void dhm_free( dhm_context *ctx );
/**
* \brief Checkup routine
*
* \return 0 if successful, or 1 if the test failed
*/
int dhm_self_test( int verbose );
#ifdef __cplusplus
}
#endif
#endif