1 /*
2 * Public key-based simple decryption 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_PK_PARSE_C) && \
25 defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
26 defined(MBEDTLS_CTR_DRBG_C)
27 #include "mbedtls/error.h"
28 #include "mbedtls/pk.h"
29 #include "mbedtls/entropy.h"
30 #include "mbedtls/ctr_drbg.h"
31
32 #include <stdio.h>
33 #include <string.h>
34 #endif
35
36 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_PK_PARSE_C) || \
37 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_ENTROPY_C) || \
38 !defined(MBEDTLS_CTR_DRBG_C)
main(void)39 int main(void)
40 {
41 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_PK_PARSE_C and/or "
42 "MBEDTLS_FS_IO and/or MBEDTLS_ENTROPY_C and/or "
43 "MBEDTLS_CTR_DRBG_C not defined.\n");
44 mbedtls_exit(0);
45 }
46 #else
47
48
main(int argc,char * argv[])49 int main(int argc, char *argv[])
50 {
51 FILE *f;
52 int ret = 1;
53 unsigned c;
54 int exit_code = MBEDTLS_EXIT_FAILURE;
55 size_t i, olen = 0;
56 mbedtls_pk_context pk;
57 mbedtls_entropy_context entropy;
58 mbedtls_ctr_drbg_context ctr_drbg;
59 unsigned char result[1024];
60 unsigned char buf[512];
61 const char *pers = "mbedtls_pk_decrypt";
62 ((void) argv);
63
64 mbedtls_pk_init(&pk);
65 mbedtls_entropy_init(&entropy);
66 mbedtls_ctr_drbg_init(&ctr_drbg);
67
68 memset(result, 0, sizeof(result));
69
70 if (argc != 2) {
71 mbedtls_printf("usage: mbedtls_pk_decrypt <key_file>\n");
72
73 #if defined(_WIN32)
74 mbedtls_printf("\n");
75 #endif
76
77 goto exit;
78 }
79
80 mbedtls_printf("\n . Seeding the random number generator...");
81 fflush(stdout);
82
83 if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
84 &entropy, (const unsigned char *) pers,
85 strlen(pers))) != 0) {
86 mbedtls_printf(" failed\n ! mbedtls_ctr_drbg_seed returned -0x%04x\n",
87 (unsigned int) -ret);
88 goto exit;
89 }
90
91 mbedtls_printf("\n . Reading private key from '%s'", argv[1]);
92 fflush(stdout);
93
94 if ((ret = mbedtls_pk_parse_keyfile(&pk, argv[1], "",
95 mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
96 mbedtls_printf(" failed\n ! mbedtls_pk_parse_keyfile returned -0x%04x\n",
97 (unsigned int) -ret);
98 goto exit;
99 }
100
101 /*
102 * Extract the RSA encrypted value from the text file
103 */
104 if ((f = fopen("result-enc.txt", "rb")) == NULL) {
105 mbedtls_printf("\n ! Could not open %s\n\n", "result-enc.txt");
106 ret = 1;
107 goto exit;
108 }
109
110 i = 0;
111 while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
112 i < (int) sizeof(buf)) {
113 buf[i++] = (unsigned char) c;
114 }
115
116 fclose(f);
117
118 /*
119 * Decrypt the encrypted RSA data and print the result.
120 */
121 mbedtls_printf("\n . Decrypting the encrypted data");
122 fflush(stdout);
123
124 if ((ret = mbedtls_pk_decrypt(&pk, buf, i, result, &olen, sizeof(result),
125 mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
126 mbedtls_printf(" failed\n ! mbedtls_pk_decrypt returned -0x%04x\n",
127 (unsigned int) -ret);
128 goto exit;
129 }
130
131 mbedtls_printf("\n . OK\n\n");
132
133 mbedtls_printf("The decrypted result is: '%s'\n\n", result);
134
135 exit_code = MBEDTLS_EXIT_SUCCESS;
136
137 exit:
138
139 mbedtls_pk_free(&pk);
140 mbedtls_entropy_free(&entropy);
141 mbedtls_ctr_drbg_free(&ctr_drbg);
142
143 #if defined(MBEDTLS_ERROR_C)
144 if (exit_code != MBEDTLS_EXIT_SUCCESS) {
145 mbedtls_strerror(ret, (char *) buf, sizeof(buf));
146 mbedtls_printf(" ! Last error was: %s\n", buf);
147 }
148 #endif
149
150 mbedtls_exit(exit_code);
151 }
152 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
153 MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
154