/* * Diffie-Hellman-Merkle key exchange (prime generation) * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later * * This file is provided under the Apache License 2.0, or the * GNU General Public License v2.0 or later. * * ********** * Apache License 2.0: * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * ********** * * ********** * GNU General Public License v2.0 or later: * * 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. * * ********** * * This file is part of mbed TLS (https://tls.mbed.org) */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include #include #define mbedtls_printf printf #define mbedtls_time_t time_t #define mbedtls_exit exit #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE #endif /* MBEDTLS_PLATFORM_C */ #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) || \ !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C) || \ !defined(MBEDTLS_GENPRIME) int main( void ) { mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or " "MBEDTLS_FS_IO and/or MBEDTLS_CTR_DRBG_C and/or " "MBEDTLS_GENPRIME not defined.\n"); mbedtls_exit( 0 ); } #else #include "mbedtls/bignum.h" #include "mbedtls/entropy.h" #include "mbedtls/ctr_drbg.h" #include #include #define USAGE \ "\n usage: dh_genprime param=<>...\n" \ "\n acceprable parameters:\n" \ " bits=%%d default: 2048\n" #define DFL_BITS 2048 /* * Note: G = 4 is always a quadratic residue mod P, * so it is a generator of order Q (with P = 2*Q+1). */ #define GENERATOR "4" int main( int argc, char **argv ) { int ret = 1; int exit_code = MBEDTLS_EXIT_FAILURE; mbedtls_mpi G, P, Q; mbedtls_entropy_context entropy; mbedtls_ctr_drbg_context ctr_drbg; const char *pers = "dh_genprime"; FILE *fout; int nbits = DFL_BITS; int i; char *p, *q; mbedtls_mpi_init( &G ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q ); mbedtls_ctr_drbg_init( &ctr_drbg ); mbedtls_entropy_init( &entropy ); if( argc == 0 ) { usage: mbedtls_printf( USAGE ); goto exit; } for( i = 1; i < argc; i++ ) { p = argv[i]; if( ( q = strchr( p, '=' ) ) == NULL ) goto usage; *q++ = '\0'; if( strcmp( p, "bits" ) == 0 ) { nbits = atoi( q ); if( nbits < 0 || nbits > MBEDTLS_MPI_MAX_BITS ) goto usage; } else goto usage; } if( ( ret = mbedtls_mpi_read_string( &G, 10, GENERATOR ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_read_string returned %d\n", ret ); goto exit; } mbedtls_printf( " ! Generating large primes may take minutes!\n" ); mbedtls_printf( "\n . Seeding the random number generator..." ); fflush( stdout ); if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, (const unsigned char *) pers, strlen( pers ) ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret ); goto exit; } mbedtls_printf( " ok\n . Generating the modulus, please wait..." ); fflush( stdout ); /* * This can take a long time... */ if( ( ret = mbedtls_mpi_gen_prime( &P, nbits, 1, mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_gen_prime returned %d\n\n", ret ); goto exit; } mbedtls_printf( " ok\n . Verifying that Q = (P-1)/2 is prime..." ); fflush( stdout ); if( ( ret = mbedtls_mpi_sub_int( &Q, &P, 1 ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_sub_int returned %d\n\n", ret ); goto exit; } if( ( ret = mbedtls_mpi_div_int( &Q, NULL, &Q, 2 ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_div_int returned %d\n\n", ret ); goto exit; } if( ( ret = mbedtls_mpi_is_prime( &Q, mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_is_prime returned %d\n\n", ret ); goto exit; } mbedtls_printf( " ok\n . Exporting the value in dh_prime.txt..." ); fflush( stdout ); if( ( fout = fopen( "dh_prime.txt", "wb+" ) ) == NULL ) { mbedtls_printf( " failed\n ! Could not create dh_prime.txt\n\n" ); goto exit; } if( ( ret = mbedtls_mpi_write_file( "P = ", &P, 16, fout ) != 0 ) || ( ret = mbedtls_mpi_write_file( "G = ", &G, 16, fout ) != 0 ) ) { mbedtls_printf( " failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret ); fclose( fout ); goto exit; } mbedtls_printf( " ok\n\n" ); fclose( fout ); exit_code = MBEDTLS_EXIT_SUCCESS; exit: mbedtls_mpi_free( &G ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q ); mbedtls_ctr_drbg_free( &ctr_drbg ); mbedtls_entropy_free( &entropy ); #if defined(_WIN32) mbedtls_printf( " Press Enter to exit this program.\n" ); fflush( stdout ); getchar(); #endif mbedtls_exit( exit_code ); } #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C && MBEDTLS_GENPRIME */