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/*
* Copyright (C) 2000,2001,2003 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_datum.h>
#include <x509_b64.h> /* for PKCS3 PEM decoding */
#include <gnutls_global.h>
#include <gnutls_dh.h>
#include "debug.h"
/* Replaces the prime in the static DH parameters, with a randomly
* generated one.
*/
/*-
* gnutls_dh_params_set - This function will replace the old DH parameters
* @dh_params: Is a structure will hold the prime numbers
* @prime: holds the new prime
* @generator: holds the new generator
* @bits: is the prime's number of bits. This value is ignored.
*
* This function will replace the pair of prime and generator for use in
* the Diffie-Hellman key exchange. The new parameters should be stored in the
* appropriate gnutls_datum.
*
-*/
int gnutls_dh_params_set(gnutls_dh_params dh_params, gnutls_datum prime,
gnutls_datum generator, int bits)
{
GNUTLS_MPI tmp_prime, tmp_g;
size_t siz = 0;
/* sprime is not null, because of the check_bits()
* above.
*/
siz = prime.size;
if (_gnutls_mpi_scan(&tmp_prime, prime.data, &siz)) {
gnutls_assert();
return GNUTLS_E_MPI_SCAN_FAILED;
}
siz = generator.size;
if (_gnutls_mpi_scan(&tmp_g, generator.data, &siz)) {
_gnutls_mpi_release(&tmp_prime);
gnutls_assert();
return GNUTLS_E_MPI_SCAN_FAILED;
}
/* copy the generated values to the structure
*/
dh_params->_prime = tmp_prime;
dh_params->_generator = tmp_g;
return 0;
}
/*-
* gnutls_dh_params_generate - This function will generate new DH parameters
* @prime: will hold the new prime
* @generator: will hold the new generator
* @bits: is the prime's number of bits
*
* This function will generate a new pair of prime and generator for use in
* the Diffie-Hellman key exchange. The new parameters will be allocated using
* gnutls_malloc() and will be stored in the appropriate datum.
* This function is normally very slow. An other function
* (gnutls_dh_params_set()) should be called in order to replace the
* included DH primes in the gnutls library.
*
* Note that the bits value should be one of 768, 1024, 2048, 3072 or 4096.
* Also note that the generation of new DH parameters is only usefull
* to servers. Clients use the parameters sent by the server, thus it's
* no use calling this in client side.
*
-*/
int gnutls_dh_params_generate(gnutls_datum * prime,
gnutls_datum * generator, int bits)
{
GNUTLS_MPI tmp_prime, tmp_g;
size_t siz;
if (_gnutls_dh_generate_prime(&tmp_g, &tmp_prime, bits) < 0) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
siz = 0;
_gnutls_mpi_print(NULL, &siz, tmp_g);
generator->data = gnutls_malloc(siz);
if (generator->data == NULL) {
_gnutls_mpi_release(&tmp_g);
_gnutls_mpi_release(&tmp_prime);
return GNUTLS_E_MEMORY_ERROR;
}
generator->size = siz;
_gnutls_mpi_print(generator->data, &siz, tmp_g);
siz = 0;
_gnutls_mpi_print(NULL, &siz, tmp_prime);
prime->data = gnutls_malloc(siz);
if (prime->data == NULL) {
gnutls_free(generator->data);
_gnutls_mpi_release(&tmp_g);
_gnutls_mpi_release(&tmp_prime);
return GNUTLS_E_MEMORY_ERROR;
}
prime->size = siz;
_gnutls_mpi_print(prime->data, &siz, tmp_prime);
#ifdef DEBUG
{
opaque buffer[512];
_gnutls_debug_log
("dh_params_generate: Generated %d bits prime %s, generator %s.\n",
bits, _gnutls_bin2hex(prime->data, prime->size, buffer, sizeof(buffer)),
_gnutls_bin2hex(generator->data, generator->size, buffer, sizeof(buffer)));
}
#endif
return 0;
}
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