1/*
2 *  Public key-based simple decryption program
3 *
4 *  Copyright The Mbed TLS Contributors
5 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7
8#include "mbedtls/build_info.h"
9
10#include "mbedtls/platform.h"
11
12#if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
13    defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
14    defined(MBEDTLS_CTR_DRBG_C)
15#include "mbedtls/error.h"
16#include "mbedtls/pk.h"
17#include "mbedtls/entropy.h"
18#include "mbedtls/ctr_drbg.h"
19
20#include <stdio.h>
21#include <string.h>
22#endif
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)
27int main(void)
28{
29    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_PK_PARSE_C and/or "
30                   "MBEDTLS_FS_IO and/or MBEDTLS_ENTROPY_C and/or "
31                   "MBEDTLS_CTR_DRBG_C not defined.\n");
32    mbedtls_exit(0);
33}
34#else
35
36
37int main(int argc, char *argv[])
38{
39    FILE *f;
40    int ret = 1;
41    unsigned c;
42    int exit_code = MBEDTLS_EXIT_FAILURE;
43    size_t i, olen = 0;
44    mbedtls_pk_context pk;
45    mbedtls_entropy_context entropy;
46    mbedtls_ctr_drbg_context ctr_drbg;
47    unsigned char result[1024];
48    unsigned char buf[512];
49    const char *pers = "mbedtls_pk_decrypt";
50    ((void) argv);
51
52    mbedtls_pk_init(&pk);
53    mbedtls_entropy_init(&entropy);
54    mbedtls_ctr_drbg_init(&ctr_drbg);
55
56    memset(result, 0, sizeof(result));
57
58#if defined(MBEDTLS_USE_PSA_CRYPTO)
59    psa_status_t status = psa_crypto_init();
60    if (status != PSA_SUCCESS) {
61        mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
62                        (int) status);
63        goto exit;
64    }
65#endif /* MBEDTLS_USE_PSA_CRYPTO */
66
67    if (argc != 2) {
68        mbedtls_printf("usage: mbedtls_pk_decrypt <key_file>\n");
69
70#if defined(_WIN32)
71        mbedtls_printf("\n");
72#endif
73
74        goto exit;
75    }
76
77    mbedtls_printf("\n  . Seeding the random number generator...");
78    fflush(stdout);
79
80    if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
81                                     &entropy, (const unsigned char *) pers,
82                                     strlen(pers))) != 0) {
83        mbedtls_printf(" failed\n  ! mbedtls_ctr_drbg_seed returned -0x%04x\n",
84                       (unsigned int) -ret);
85        goto exit;
86    }
87
88    mbedtls_printf("\n  . Reading private key from '%s'", argv[1]);
89    fflush(stdout);
90
91    if ((ret = mbedtls_pk_parse_keyfile(&pk, argv[1], "",
92                                        mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
93        mbedtls_printf(" failed\n  ! mbedtls_pk_parse_keyfile returned -0x%04x\n",
94                       (unsigned int) -ret);
95        goto exit;
96    }
97
98    /*
99     * Extract the RSA encrypted value from the text file
100     */
101    if ((f = fopen("result-enc.txt", "rb")) == NULL) {
102        mbedtls_printf("\n  ! Could not open %s\n\n", "result-enc.txt");
103        ret = 1;
104        goto exit;
105    }
106
107    i = 0;
108    while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
109           i < (int) sizeof(buf)) {
110        buf[i++] = (unsigned char) c;
111    }
112
113    fclose(f);
114
115    /*
116     * Decrypt the encrypted RSA data and print the result.
117     */
118    mbedtls_printf("\n  . Decrypting the encrypted data");
119    fflush(stdout);
120
121    if ((ret = mbedtls_pk_decrypt(&pk, buf, i, result, &olen, sizeof(result),
122                                  mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
123        mbedtls_printf(" failed\n  ! mbedtls_pk_decrypt returned -0x%04x\n",
124                       (unsigned int) -ret);
125        goto exit;
126    }
127
128    mbedtls_printf("\n  . OK\n\n");
129
130    mbedtls_printf("The decrypted result is: '%s'\n\n", result);
131
132    exit_code = MBEDTLS_EXIT_SUCCESS;
133
134exit:
135
136    mbedtls_pk_free(&pk);
137    mbedtls_entropy_free(&entropy);
138    mbedtls_ctr_drbg_free(&ctr_drbg);
139#if defined(MBEDTLS_USE_PSA_CRYPTO)
140    mbedtls_psa_crypto_free();
141#endif /* MBEDTLS_USE_PSA_CRYPTO */
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