1 /*
2 * Example ECDSA program
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_exit exit
35 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
36 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
37 #endif /* MBEDTLS_PLATFORM_C */
38
39 #if defined(MBEDTLS_ECDSA_C) && \
40 defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
41 #include "mbedtls/entropy.h"
42 #include "mbedtls/ctr_drbg.h"
43 #include "mbedtls/ecdsa.h"
44 #include "mbedtls/sha256.h"
45
46 #include <string.h>
47 #endif
48
49 /*
50 * Uncomment to show key and signature details
51 */
52 #define VERBOSE
53
54 /*
55 * Uncomment to force use of a specific curve
56 */
57 #define ECPARAMS MBEDTLS_ECP_DP_SECP192R1
58
59 #if !defined(ECPARAMS)
60 #define ECPARAMS mbedtls_ecp_curve_list()->grp_id
61 #endif
62
63 #if !defined(MBEDTLS_ECDSA_C) || !defined(MBEDTLS_SHA256_C) || \
64 !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C)
main(void)65 int main( void )
66 {
67 mbedtls_printf("MBEDTLS_ECDSA_C and/or MBEDTLS_SHA256_C and/or "
68 "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C not defined\n");
69 return( 0 );
70 }
71 #else
72 #if defined(VERBOSE)
dump_buf(const char * title,unsigned char * buf,size_t len)73 static void dump_buf( const char *title, unsigned char *buf, size_t len )
74 {
75 size_t i;
76
77 mbedtls_printf( "%s", title );
78 for( i = 0; i < len; i++ )
79 mbedtls_printf("%c%c", "0123456789ABCDEF" [buf[i] / 16],
80 "0123456789ABCDEF" [buf[i] % 16] );
81 mbedtls_printf( "\n" );
82 }
83
dump_pubkey(const char * title,mbedtls_ecdsa_context * key)84 static void dump_pubkey( const char *title, mbedtls_ecdsa_context *key )
85 {
86 unsigned char buf[300];
87 size_t len;
88
89 if( mbedtls_ecp_point_write_binary( &key->grp, &key->Q,
90 MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof buf ) != 0 )
91 {
92 mbedtls_printf("internal error\n");
93 return;
94 }
95
96 dump_buf( title, buf, len );
97 }
98 #else
99 #define dump_buf( a, b, c )
100 #define dump_pubkey( a, b )
101 #endif
102
103 #if defined(MBEDTLS_CHECK_PARAMS)
104 #include "mbedtls/platform_util.h"
mbedtls_param_failed(const char * failure_condition,const char * file,int line)105 void mbedtls_param_failed( const char *failure_condition,
106 const char *file,
107 int line )
108 {
109 mbedtls_printf( "%s:%i: Input param failed - %s\n",
110 file, line, failure_condition );
111 mbedtls_exit( MBEDTLS_EXIT_FAILURE );
112 }
113 #endif
114
main(int argc,char * argv[])115 int main( int argc, char *argv[] )
116 {
117 int ret = 1;
118 int exit_code = MBEDTLS_EXIT_FAILURE;
119 mbedtls_ecdsa_context ctx_sign, ctx_verify;
120 mbedtls_entropy_context entropy;
121 mbedtls_ctr_drbg_context ctr_drbg;
122 unsigned char message[100];
123 unsigned char hash[32];
124 unsigned char sig[MBEDTLS_ECDSA_MAX_LEN];
125 size_t sig_len;
126 const char *pers = "ecdsa";
127 ((void) argv);
128
129 mbedtls_ecdsa_init( &ctx_sign );
130 mbedtls_ecdsa_init( &ctx_verify );
131 mbedtls_ctr_drbg_init( &ctr_drbg );
132
133 memset( sig, 0, sizeof( sig ) );
134 memset( message, 0x25, sizeof( message ) );
135
136 if( argc != 1 )
137 {
138 mbedtls_printf( "usage: ecdsa\n" );
139
140 #if defined(_WIN32)
141 mbedtls_printf( "\n" );
142 #endif
143
144 goto exit;
145 }
146
147 /*
148 * Generate a key pair for signing
149 */
150 mbedtls_printf( "\n . Seeding the random number generator..." );
151 fflush( stdout );
152
153 mbedtls_entropy_init( &entropy );
154 if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
155 (const unsigned char *) pers,
156 strlen( pers ) ) ) != 0 )
157 {
158 mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
159 goto exit;
160 }
161
162 mbedtls_printf( " ok\n . Generating key pair..." );
163 fflush( stdout );
164
165 if( ( ret = mbedtls_ecdsa_genkey( &ctx_sign, ECPARAMS,
166 mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
167 {
168 mbedtls_printf( " failed\n ! mbedtls_ecdsa_genkey returned %d\n", ret );
169 goto exit;
170 }
171
172 mbedtls_printf( " ok (key size: %d bits)\n", (int) ctx_sign.grp.pbits );
173
174 dump_pubkey( " + Public key: ", &ctx_sign );
175
176 /*
177 * Compute message hash
178 */
179 mbedtls_printf( " . Computing message hash..." );
180 fflush( stdout );
181
182 if( ( ret = mbedtls_sha256_ret( message, sizeof( message ), hash, 0 ) ) != 0 )
183 {
184 mbedtls_printf( " failed\n ! mbedtls_sha256_ret returned %d\n", ret );
185 goto exit;
186 }
187
188 mbedtls_printf( " ok\n" );
189
190 dump_buf( " + Hash: ", hash, sizeof( hash ) );
191
192 /*
193 * Sign message hash
194 */
195 mbedtls_printf( " . Signing message hash..." );
196 fflush( stdout );
197
198 if( ( ret = mbedtls_ecdsa_write_signature( &ctx_sign, MBEDTLS_MD_SHA256,
199 hash, sizeof( hash ),
200 sig, &sig_len,
201 mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
202 {
203 mbedtls_printf( " failed\n ! mbedtls_ecdsa_genkey returned %d\n", ret );
204 goto exit;
205 }
206 mbedtls_printf( " ok (signature length = %u)\n", (unsigned int) sig_len );
207
208 dump_buf( " + Signature: ", sig, sig_len );
209
210 /*
211 * Transfer public information to verifying context
212 *
213 * We could use the same context for verification and signatures, but we
214 * chose to use a new one in order to make it clear that the verifying
215 * context only needs the public key (Q), and not the private key (d).
216 */
217 mbedtls_printf( " . Preparing verification context..." );
218 fflush( stdout );
219
220 if( ( ret = mbedtls_ecp_group_copy( &ctx_verify.grp, &ctx_sign.grp ) ) != 0 )
221 {
222 mbedtls_printf( " failed\n ! mbedtls_ecp_group_copy returned %d\n", ret );
223 goto exit;
224 }
225
226 if( ( ret = mbedtls_ecp_copy( &ctx_verify.Q, &ctx_sign.Q ) ) != 0 )
227 {
228 mbedtls_printf( " failed\n ! mbedtls_ecp_copy returned %d\n", ret );
229 goto exit;
230 }
231
232 /*
233 * Verify signature
234 */
235 mbedtls_printf( " ok\n . Verifying signature..." );
236 fflush( stdout );
237
238 if( ( ret = mbedtls_ecdsa_read_signature( &ctx_verify,
239 hash, sizeof( hash ),
240 sig, sig_len ) ) != 0 )
241 {
242 mbedtls_printf( " failed\n ! mbedtls_ecdsa_read_signature returned %d\n", ret );
243 goto exit;
244 }
245
246 mbedtls_printf( " ok\n" );
247
248 exit_code = MBEDTLS_EXIT_SUCCESS;
249
250 exit:
251
252 #if defined(_WIN32)
253 mbedtls_printf( " + Press Enter to exit this program.\n" );
254 fflush( stdout ); getchar();
255 #endif
256
257 mbedtls_ecdsa_free( &ctx_verify );
258 mbedtls_ecdsa_free( &ctx_sign );
259 mbedtls_ctr_drbg_free( &ctr_drbg );
260 mbedtls_entropy_free( &entropy );
261
262 return( exit_code );
263 }
264 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
265 ECPARAMS */
266