1 /*
2 * Example RSA key generation program
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7
8 #if !defined(MBEDTLS_CONFIG_FILE)
9 #include "mbedtls/config.h"
10 #else
11 #include MBEDTLS_CONFIG_FILE
12 #endif
13
14 #include "mbedtls/platform.h"
15
16 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_ENTROPY_C) && \
17 defined(MBEDTLS_RSA_C) && defined(MBEDTLS_GENPRIME) && \
18 defined(MBEDTLS_FS_IO) && defined(MBEDTLS_CTR_DRBG_C)
19 #include "mbedtls/entropy.h"
20 #include "mbedtls/ctr_drbg.h"
21 #include "mbedtls/bignum.h"
22 #include "mbedtls/rsa.h"
23
24 #include <stdio.h>
25 #include <string.h>
26 #endif
27
28 #define KEY_SIZE 2048
29 #define EXPONENT 65537
30
31 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) || \
32 !defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_GENPRIME) || \
33 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C)
main(void)34 int main(void)
35 {
36 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
37 "MBEDTLS_RSA_C and/or MBEDTLS_GENPRIME and/or "
38 "MBEDTLS_FS_IO and/or MBEDTLS_CTR_DRBG_C not defined.\n");
39 mbedtls_exit(0);
40 }
41 #else
42
43
main(void)44 int main(void)
45 {
46 int ret = 1;
47 int exit_code = MBEDTLS_EXIT_FAILURE;
48 mbedtls_rsa_context rsa;
49 mbedtls_entropy_context entropy;
50 mbedtls_ctr_drbg_context ctr_drbg;
51 mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;
52 FILE *fpub = NULL;
53 FILE *fpriv = NULL;
54 const char *pers = "rsa_genkey";
55
56 mbedtls_ctr_drbg_init(&ctr_drbg);
57 mbedtls_rsa_init(&rsa, MBEDTLS_RSA_PKCS_V15, 0);
58 mbedtls_mpi_init(&N); mbedtls_mpi_init(&P); mbedtls_mpi_init(&Q);
59 mbedtls_mpi_init(&D); mbedtls_mpi_init(&E); mbedtls_mpi_init(&DP);
60 mbedtls_mpi_init(&DQ); mbedtls_mpi_init(&QP);
61
62 mbedtls_printf("\n . Seeding the random number generator...");
63 fflush(stdout);
64
65 mbedtls_entropy_init(&entropy);
66 if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
67 (const unsigned char *) pers,
68 strlen(pers))) != 0) {
69 mbedtls_printf(" failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret);
70 goto exit;
71 }
72
73 mbedtls_printf(" ok\n . Generating the RSA key [ %d-bit ]...", KEY_SIZE);
74 fflush(stdout);
75
76 if ((ret = mbedtls_rsa_gen_key(&rsa, mbedtls_ctr_drbg_random, &ctr_drbg, KEY_SIZE,
77 EXPONENT)) != 0) {
78 mbedtls_printf(" failed\n ! mbedtls_rsa_gen_key returned %d\n\n", ret);
79 goto exit;
80 }
81
82 mbedtls_printf(" ok\n . Exporting the public key in rsa_pub.txt....");
83 fflush(stdout);
84
85 if ((ret = mbedtls_rsa_export(&rsa, &N, &P, &Q, &D, &E)) != 0 ||
86 (ret = mbedtls_rsa_export_crt(&rsa, &DP, &DQ, &QP)) != 0) {
87 mbedtls_printf(" failed\n ! could not export RSA parameters\n\n");
88 goto exit;
89 }
90
91 if ((fpub = fopen("rsa_pub.txt", "wb+")) == NULL) {
92 mbedtls_printf(" failed\n ! could not open rsa_pub.txt for writing\n\n");
93 goto exit;
94 }
95
96 if ((ret = mbedtls_mpi_write_file("N = ", &N, 16, fpub)) != 0 ||
97 (ret = mbedtls_mpi_write_file("E = ", &E, 16, fpub)) != 0) {
98 mbedtls_printf(" failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret);
99 goto exit;
100 }
101
102 mbedtls_printf(" ok\n . Exporting the private key in rsa_priv.txt...");
103 fflush(stdout);
104
105 if ((fpriv = fopen("rsa_priv.txt", "wb+")) == NULL) {
106 mbedtls_printf(" failed\n ! could not open rsa_priv.txt for writing\n");
107 goto exit;
108 }
109
110 if ((ret = mbedtls_mpi_write_file("N = ", &N, 16, fpriv)) != 0 ||
111 (ret = mbedtls_mpi_write_file("E = ", &E, 16, fpriv)) != 0 ||
112 (ret = mbedtls_mpi_write_file("D = ", &D, 16, fpriv)) != 0 ||
113 (ret = mbedtls_mpi_write_file("P = ", &P, 16, fpriv)) != 0 ||
114 (ret = mbedtls_mpi_write_file("Q = ", &Q, 16, fpriv)) != 0 ||
115 (ret = mbedtls_mpi_write_file("DP = ", &DP, 16, fpriv)) != 0 ||
116 (ret = mbedtls_mpi_write_file("DQ = ", &DQ, 16, fpriv)) != 0 ||
117 (ret = mbedtls_mpi_write_file("QP = ", &QP, 16, fpriv)) != 0) {
118 mbedtls_printf(" failed\n ! mbedtls_mpi_write_file returned %d\n\n", ret);
119 goto exit;
120 }
121 mbedtls_printf(" ok\n\n");
122
123 exit_code = MBEDTLS_EXIT_SUCCESS;
124
125 exit:
126
127 if (fpub != NULL) {
128 fclose(fpub);
129 }
130
131 if (fpriv != NULL) {
132 fclose(fpriv);
133 }
134
135 mbedtls_mpi_free(&N); mbedtls_mpi_free(&P); mbedtls_mpi_free(&Q);
136 mbedtls_mpi_free(&D); mbedtls_mpi_free(&E); mbedtls_mpi_free(&DP);
137 mbedtls_mpi_free(&DQ); mbedtls_mpi_free(&QP);
138 mbedtls_rsa_free(&rsa);
139 mbedtls_ctr_drbg_free(&ctr_drbg);
140 mbedtls_entropy_free(&entropy);
141
142 #if defined(_WIN32)
143 mbedtls_printf(" Press Enter to exit this program.\n");
144 fflush(stdout); getchar();
145 #endif
146
147 mbedtls_exit(exit_code);
148 }
149 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_RSA_C &&
150 MBEDTLS_GENPRIME && MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
151