1 /*
2 * Diffie-Hellman-Merkle key exchange (prime generation)
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21
22 #if !defined(MBEDTLS_CONFIG_FILE)
23 #include "mbedtls/config.h"
24 #else
25 #include MBEDTLS_CONFIG_FILE
26 #endif
27
28 #if defined(MBEDTLS_PLATFORM_C)
29 #include "mbedtls/platform.h"
30 #else
31 #include <stdio.h>
32 #include <stdlib.h>
33 #define mbedtls_printf printf
34 #define mbedtls_time_t time_t
35 #define mbedtls_exit exit
36 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
37 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
38 #endif /* MBEDTLS_PLATFORM_C */
39
40 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) || \
41 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C) || \
42 !defined(MBEDTLS_GENPRIME)
main(void)43 int main( void )
44 {
45 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
46 "MBEDTLS_FS_IO and/or MBEDTLS_CTR_DRBG_C and/or "
47 "MBEDTLS_GENPRIME not defined.\n");
48 return( 0 );
49 }
50 #else
51
52 #include "mbedtls/bignum.h"
53 #include "mbedtls/entropy.h"
54 #include "mbedtls/ctr_drbg.h"
55
56 #include <stdio.h>
57 #include <string.h>
58
59 #define USAGE \
60 "\n usage: dh_genprime param=<>...\n" \
61 "\n acceprable parameters:\n" \
62 " bits=%%d default: 2048\n"
63
64 #define DFL_BITS 2048
65
66 /*
67 * Note: G = 4 is always a quadratic residue mod P,
68 * so it is a generator of order Q (with P = 2*Q+1).
69 */
70 #define GENERATOR "4"
71
72 #if defined(MBEDTLS_CHECK_PARAMS)
73 #include "mbedtls/platform_util.h"
mbedtls_param_failed(const char * failure_condition,const char * file,int line)74 void mbedtls_param_failed( const char *failure_condition,
75 const char *file,
76 int line )
77 {
78 mbedtls_printf( "%s:%i: Input param failed - %s\n",
79 file, line, failure_condition );
80 mbedtls_exit( MBEDTLS_EXIT_FAILURE );
81 }
82 #endif
83
main(int argc,char ** argv)84 int main( int argc, char **argv )
85 {
86 int ret = 1;
87 int exit_code = MBEDTLS_EXIT_FAILURE;
88 mbedtls_mpi G, P, Q;
89 mbedtls_entropy_context entropy;
90 mbedtls_ctr_drbg_context ctr_drbg;
91 const char *pers = "dh_genprime";
92 FILE *fout;
93 int nbits = DFL_BITS;
94 int i;
95 char *p, *q;
96
97 mbedtls_mpi_init( &G ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q );
98 mbedtls_ctr_drbg_init( &ctr_drbg );
99 mbedtls_entropy_init( &entropy );
100
101 if( argc == 0 )
102 {
103 usage:
104 mbedtls_printf( USAGE );
105 return( exit_code );
106 }
107
108 for( i = 1; i < argc; i++ )
109 {
110 p = argv[i];
111 if( ( q = strchr( p, '=' ) ) == NULL )
112 goto usage;
113 *q++ = '\0';
114
115 if( strcmp( p, "bits" ) == 0 )
116 {
117 nbits = atoi( q );
118 if( nbits < 0 || nbits > MBEDTLS_MPI_MAX_BITS )
119 goto usage;
120 }
121 else
122 goto usage;
123 }
124
125 if( ( ret = mbedtls_mpi_read_string( &G, 10, GENERATOR ) ) != 0 )
126 {
127 mbedtls_printf( " failed\n ! mbedtls_mpi_read_string returned %d\n", ret );
128 goto exit;
129 }
130
131 mbedtls_printf( " ! Generating large primes may take minutes!\n" );
132
133 mbedtls_printf( "\n . Seeding the random number generator..." );
134 fflush( stdout );
135
136 if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
137 (const unsigned char *) pers,
138 strlen( pers ) ) ) != 0 )
139 {
140 mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
141 goto exit;
142 }
143
144 mbedtls_printf( " ok\n . Generating the modulus, please wait..." );
145 fflush( stdout );
146
147 /*
148 * This can take a long time...
149 */
150 if( ( ret = mbedtls_mpi_gen_prime( &P, nbits, 1,
151 mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
152 {
153 mbedtls_printf( " failed\n ! mbedtls_mpi_gen_prime returned %d\n\n", ret );
154 goto exit;
155 }
156
157 mbedtls_printf( " ok\n . Verifying that Q = (P-1)/2 is prime..." );
158 fflush( stdout );
159
160 if( ( ret = mbedtls_mpi_sub_int( &Q, &P, 1 ) ) != 0 )
161 {
162 mbedtls_printf( " failed\n ! mbedtls_mpi_sub_int returned %d\n\n", ret );
163 goto exit;
164 }
165
166 if( ( ret = mbedtls_mpi_div_int( &Q, NULL, &Q, 2 ) ) != 0 )
167 {
168 mbedtls_printf( " failed\n ! mbedtls_mpi_div_int returned %d\n\n", ret );
169 goto exit;
170 }
171
172 if( ( ret = mbedtls_mpi_is_prime_ext( &Q, 50, mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
173 {
174 mbedtls_printf( " failed\n ! mbedtls_mpi_is_prime returned %d\n\n", ret );
175 goto exit;
176 }
177
178 mbedtls_printf( " ok\n . Exporting the value in dh_prime.txt..." );
179 fflush( stdout );
180
181 if( ( fout = fopen( "dh_prime.txt", "wb+" ) ) == NULL )
182 {
183 mbedtls_printf( " failed\n ! Could not create dh_prime.txt\n\n" );
184 goto exit;
185 }
186
187 if( ( ret = mbedtls_mpi_write_file( "P = ", &P, 16, fout ) != 0 ) ||
188 ( ret = mbedtls_mpi_write_file( "G = ", &G, 16, fout ) != 0 ) )
189 {
190 mbedtls_printf( " failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret );
191 fclose( fout );
192 goto exit;
193 }
194
195 mbedtls_printf( " ok\n\n" );
196 fclose( fout );
197
198 exit_code = MBEDTLS_EXIT_SUCCESS;
199
200 exit:
201
202 mbedtls_mpi_free( &G ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
203 mbedtls_ctr_drbg_free( &ctr_drbg );
204 mbedtls_entropy_free( &entropy );
205
206 #if defined(_WIN32)
207 mbedtls_printf( " Press Enter to exit this program.\n" );
208 fflush( stdout ); getchar();
209 #endif
210
211 return( exit_code );
212 }
213 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_FS_IO &&
214 MBEDTLS_CTR_DRBG_C && MBEDTLS_GENPRIME */
215