1 /*
2 * Example RSA key generation program
3 *
4 * Copyright The Mbed TLS Contributors
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
20 #include "mbedtls/build_info.h"
21
22 #include "mbedtls/platform.h"
23
24 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_ENTROPY_C) && \
25 defined(MBEDTLS_RSA_C) && defined(MBEDTLS_GENPRIME) && \
26 defined(MBEDTLS_FS_IO) && defined(MBEDTLS_CTR_DRBG_C)
27 #include "mbedtls/entropy.h"
28 #include "mbedtls/ctr_drbg.h"
29 #include "mbedtls/bignum.h"
30 #include "mbedtls/rsa.h"
31
32 #include <stdio.h>
33 #include <string.h>
34 #endif
35
36 #define KEY_SIZE 2048
37 #define EXPONENT 65537
38
39 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) || \
40 !defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_GENPRIME) || \
41 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C)
main(void)42 int main(void)
43 {
44 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
45 "MBEDTLS_RSA_C and/or MBEDTLS_GENPRIME and/or "
46 "MBEDTLS_FS_IO and/or MBEDTLS_CTR_DRBG_C not defined.\n");
47 mbedtls_exit(0);
48 }
49 #else
50
51
main(void)52 int main(void)
53 {
54 int ret = 1;
55 int exit_code = MBEDTLS_EXIT_FAILURE;
56 mbedtls_rsa_context rsa;
57 mbedtls_entropy_context entropy;
58 mbedtls_ctr_drbg_context ctr_drbg;
59 mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;
60 FILE *fpub = NULL;
61 FILE *fpriv = NULL;
62 const char *pers = "rsa_genkey";
63
64 mbedtls_ctr_drbg_init(&ctr_drbg);
65 mbedtls_rsa_init(&rsa);
66 mbedtls_mpi_init(&N); mbedtls_mpi_init(&P); mbedtls_mpi_init(&Q);
67 mbedtls_mpi_init(&D); mbedtls_mpi_init(&E); mbedtls_mpi_init(&DP);
68 mbedtls_mpi_init(&DQ); mbedtls_mpi_init(&QP);
69
70 mbedtls_printf("\n . Seeding the random number generator...");
71 fflush(stdout);
72
73 mbedtls_entropy_init(&entropy);
74 if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
75 (const unsigned char *) pers,
76 strlen(pers))) != 0) {
77 mbedtls_printf(" failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret);
78 goto exit;
79 }
80
81 mbedtls_printf(" ok\n . Generating the RSA key [ %d-bit ]...", KEY_SIZE);
82 fflush(stdout);
83
84 if ((ret = mbedtls_rsa_gen_key(&rsa, mbedtls_ctr_drbg_random, &ctr_drbg, KEY_SIZE,
85 EXPONENT)) != 0) {
86 mbedtls_printf(" failed\n ! mbedtls_rsa_gen_key returned %d\n\n", ret);
87 goto exit;
88 }
89
90 mbedtls_printf(" ok\n . Exporting the public key in rsa_pub.txt....");
91 fflush(stdout);
92
93 if ((ret = mbedtls_rsa_export(&rsa, &N, &P, &Q, &D, &E)) != 0 ||
94 (ret = mbedtls_rsa_export_crt(&rsa, &DP, &DQ, &QP)) != 0) {
95 mbedtls_printf(" failed\n ! could not export RSA parameters\n\n");
96 goto exit;
97 }
98
99 if ((fpub = fopen("rsa_pub.txt", "wb+")) == NULL) {
100 mbedtls_printf(" failed\n ! could not open rsa_pub.txt for writing\n\n");
101 goto exit;
102 }
103
104 if ((ret = mbedtls_mpi_write_file("N = ", &N, 16, fpub)) != 0 ||
105 (ret = mbedtls_mpi_write_file("E = ", &E, 16, fpub)) != 0) {
106 mbedtls_printf(" failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret);
107 goto exit;
108 }
109
110 mbedtls_printf(" ok\n . Exporting the private key in rsa_priv.txt...");
111 fflush(stdout);
112
113 if ((fpriv = fopen("rsa_priv.txt", "wb+")) == NULL) {
114 mbedtls_printf(" failed\n ! could not open rsa_priv.txt for writing\n");
115 goto exit;
116 }
117
118 if ((ret = mbedtls_mpi_write_file("N = ", &N, 16, fpriv)) != 0 ||
119 (ret = mbedtls_mpi_write_file("E = ", &E, 16, fpriv)) != 0 ||
120 (ret = mbedtls_mpi_write_file("D = ", &D, 16, fpriv)) != 0 ||
121 (ret = mbedtls_mpi_write_file("P = ", &P, 16, fpriv)) != 0 ||
122 (ret = mbedtls_mpi_write_file("Q = ", &Q, 16, fpriv)) != 0 ||
123 (ret = mbedtls_mpi_write_file("DP = ", &DP, 16, fpriv)) != 0 ||
124 (ret = mbedtls_mpi_write_file("DQ = ", &DQ, 16, fpriv)) != 0 ||
125 (ret = mbedtls_mpi_write_file("QP = ", &QP, 16, fpriv)) != 0) {
126 mbedtls_printf(" failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret);
127 goto exit;
128 }
129 mbedtls_printf(" ok\n\n");
130
131 exit_code = MBEDTLS_EXIT_SUCCESS;
132
133 exit:
134
135 if (fpub != NULL) {
136 fclose(fpub);
137 }
138
139 if (fpriv != NULL) {
140 fclose(fpriv);
141 }
142
143 mbedtls_mpi_free(&N); mbedtls_mpi_free(&P); mbedtls_mpi_free(&Q);
144 mbedtls_mpi_free(&D); mbedtls_mpi_free(&E); mbedtls_mpi_free(&DP);
145 mbedtls_mpi_free(&DQ); mbedtls_mpi_free(&QP);
146 mbedtls_rsa_free(&rsa);
147 mbedtls_ctr_drbg_free(&ctr_drbg);
148 mbedtls_entropy_free(&entropy);
149
150 mbedtls_exit(exit_code);
151 }
152 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_RSA_C &&
153 MBEDTLS_GENPRIME && MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
154
