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 #if defined(MBEDTLS_PLATFORM_C)
23 #include "mbedtls/platform.h"
24 #else
25 #include <stdio.h>
26 #include <stdlib.h>
27 #define mbedtls_printf printf
28 #define mbedtls_exit exit
29 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
30 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
31 #endif /* MBEDTLS_PLATFORM_C */
32
33 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
34 defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
35 defined(MBEDTLS_CTR_DRBG_C)
36 #include "mbedtls/error.h"
37 #include "mbedtls/pk.h"
38 #include "mbedtls/entropy.h"
39 #include "mbedtls/ctr_drbg.h"
40
41 #include <stdio.h>
42 #include <string.h>
43 #endif
44
45 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_PK_PARSE_C) || \
46 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_ENTROPY_C) || \
47 !defined(MBEDTLS_CTR_DRBG_C)
main(void)48 int main( void )
49 {
50 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_PK_PARSE_C and/or "
51 "MBEDTLS_FS_IO and/or MBEDTLS_ENTROPY_C and/or "
52 "MBEDTLS_CTR_DRBG_C not defined.\n");
53 mbedtls_exit( 0 );
54 }
55 #else
56
57
main(int argc,char * argv[])58 int main( int argc, char *argv[] )
59 {
60 FILE *f;
61 int ret = 1;
62 unsigned c;
63 int exit_code = MBEDTLS_EXIT_FAILURE;
64 size_t i, olen = 0;
65 mbedtls_pk_context pk;
66 mbedtls_entropy_context entropy;
67 mbedtls_ctr_drbg_context ctr_drbg;
68 unsigned char result[1024];
69 unsigned char buf[512];
70 const char *pers = "mbedtls_pk_decrypt";
71 ((void) argv);
72
73 mbedtls_pk_init( &pk );
74 mbedtls_entropy_init( &entropy );
75 mbedtls_ctr_drbg_init( &ctr_drbg );
76
77 memset(result, 0, sizeof( result ) );
78
79 if( argc != 2 )
80 {
81 mbedtls_printf( "usage: mbedtls_pk_decrypt <key_file>\n" );
82
83 #if defined(_WIN32)
84 mbedtls_printf( "\n" );
85 #endif
86
87 goto exit;
88 }
89
90 mbedtls_printf( "\n . Seeding the random number generator..." );
91 fflush( stdout );
92
93 if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
94 &entropy, (const unsigned char *) pers,
95 strlen( pers ) ) ) != 0 )
96 {
97 mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned -0x%04x\n",
98 (unsigned int) -ret );
99 goto exit;
100 }
101
102 mbedtls_printf( "\n . Reading private key from '%s'", argv[1] );
103 fflush( stdout );
104
105 if( ( ret = mbedtls_pk_parse_keyfile( &pk, argv[1], "",
106 mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
107 {
108 mbedtls_printf( " failed\n ! mbedtls_pk_parse_keyfile returned -0x%04x\n", (unsigned int) -ret );
109 goto exit;
110 }
111
112 /*
113 * Extract the RSA encrypted value from the text file
114 */
115 if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL )
116 {
117 mbedtls_printf( "\n ! Could not open %s\n\n", "result-enc.txt" );
118 ret = 1;
119 goto exit;
120 }
121
122 i = 0;
123 while( fscanf( f, "%02X", (unsigned int*) &c ) > 0 &&
124 i < (int) sizeof( buf ) )
125 {
126 buf[i++] = (unsigned char) c;
127 }
128
129 fclose( f );
130
131 /*
132 * Decrypt the encrypted RSA data and print the result.
133 */
134 mbedtls_printf( "\n . Decrypting the encrypted data" );
135 fflush( stdout );
136
137 if( ( ret = mbedtls_pk_decrypt( &pk, buf, i, result, &olen, sizeof(result),
138 mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
139 {
140 mbedtls_printf( " failed\n ! mbedtls_pk_decrypt returned -0x%04x\n",
141 (unsigned int) -ret );
142 goto exit;
143 }
144
145 mbedtls_printf( "\n . OK\n\n" );
146
147 mbedtls_printf( "The decrypted result is: '%s'\n\n", result );
148
149 exit_code = MBEDTLS_EXIT_SUCCESS;
150
151 exit:
152
153 mbedtls_pk_free( &pk );
154 mbedtls_entropy_free( &entropy );
155 mbedtls_ctr_drbg_free( &ctr_drbg );
156
157 #if defined(MBEDTLS_ERROR_C)
158 if( exit_code != MBEDTLS_EXIT_SUCCESS )
159 {
160 mbedtls_strerror( ret, (char *) buf, sizeof( buf ) );
161 mbedtls_printf( " ! Last error was: %s\n", buf );
162 }
163 #endif
164
165 #if defined(_WIN32)
166 mbedtls_printf( " + Press Enter to exit this program.\n" );
167 fflush( stdout ); getchar();
168 #endif
169
170 mbedtls_exit( exit_code );
171 }
172 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
173 MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
174