1 /*
2  *  RSA simple data encryption 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_fprintf         fprintf
28 #define mbedtls_printf          printf
29 #define mbedtls_exit            exit
30 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
31 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
32 #endif /* MBEDTLS_PLATFORM_C */
33 
34 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_RSA_C) && \
35     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO) && \
36     defined(MBEDTLS_CTR_DRBG_C)
37 #include "mbedtls/rsa.h"
38 #include "mbedtls/entropy.h"
39 #include "mbedtls/ctr_drbg.h"
40 
41 #include <string.h>
42 #endif
43 
44 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
45     !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_FS_IO) || \
46     !defined(MBEDTLS_CTR_DRBG_C)
main(void)47 int main( void )
48 {
49     mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
50            "MBEDTLS_ENTROPY_C and/or MBEDTLS_FS_IO and/or "
51            "MBEDTLS_CTR_DRBG_C not defined.\n");
52     mbedtls_exit( 0 );
53 }
54 #else
55 
56 
main(int argc,char * argv[])57 int main( int argc, char *argv[] )
58 {
59     FILE *f;
60     int ret = 1;
61     int exit_code = MBEDTLS_EXIT_FAILURE;
62     size_t i;
63     mbedtls_rsa_context rsa;
64     mbedtls_entropy_context entropy;
65     mbedtls_ctr_drbg_context ctr_drbg;
66     unsigned char input[1024];
67     unsigned char buf[512];
68     const char *pers = "rsa_encrypt";
69     mbedtls_mpi N, E;
70 
71     if( argc != 2 )
72     {
73         mbedtls_printf( "usage: rsa_encrypt <string of max 100 characters>\n" );
74 
75 #if defined(_WIN32)
76         mbedtls_printf( "\n" );
77 #endif
78 
79         mbedtls_exit( exit_code );
80     }
81 
82     mbedtls_printf( "\n  . Seeding the random number generator..." );
83     fflush( stdout );
84 
85     mbedtls_mpi_init( &N ); mbedtls_mpi_init( &E );
86     mbedtls_rsa_init( &rsa );
87     mbedtls_ctr_drbg_init( &ctr_drbg );
88     mbedtls_entropy_init( &entropy );
89 
90     ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
91                                  &entropy, (const unsigned char *) pers,
92                                  strlen( pers ) );
93     if( ret != 0 )
94     {
95         mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n",
96                         ret );
97         goto exit;
98     }
99 
100     mbedtls_printf( "\n  . Reading public key from rsa_pub.txt" );
101     fflush( stdout );
102 
103     if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
104     {
105         mbedtls_printf( " failed\n  ! Could not open rsa_pub.txt\n" \
106                 "  ! Please run rsa_genkey first\n\n" );
107         goto exit;
108     }
109 
110     if( ( ret = mbedtls_mpi_read_file( &N, 16, f ) ) != 0 ||
111         ( ret = mbedtls_mpi_read_file( &E, 16, f ) ) != 0 )
112     {
113         mbedtls_printf( " failed\n  ! mbedtls_mpi_read_file returned %d\n\n",
114                         ret );
115         fclose( f );
116         goto exit;
117     }
118     fclose( f );
119 
120     if( ( ret = mbedtls_rsa_import( &rsa, &N, NULL, NULL, NULL, &E ) ) != 0 )
121     {
122         mbedtls_printf( " failed\n  ! mbedtls_rsa_import returned %d\n\n",
123                         ret );
124         goto exit;
125     }
126 
127     if( strlen( argv[1] ) > 100 )
128     {
129         mbedtls_printf( " Input data larger than 100 characters.\n\n" );
130         goto exit;
131     }
132 
133     memcpy( input, argv[1], strlen( argv[1] ) );
134 
135     /*
136      * Calculate the RSA encryption of the hash.
137      */
138     mbedtls_printf( "\n  . Generating the RSA encrypted value" );
139     fflush( stdout );
140 
141     ret = mbedtls_rsa_pkcs1_encrypt( &rsa, mbedtls_ctr_drbg_random,
142                                      &ctr_drbg, strlen( argv[1] ), input, buf );
143     if( ret != 0 )
144     {
145         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_encrypt returned %d\n\n",
146                         ret );
147         goto exit;
148     }
149 
150     /*
151      * Write the signature into result-enc.txt
152      */
153     if( ( f = fopen( "result-enc.txt", "wb+" ) ) == NULL )
154     {
155         mbedtls_printf( " failed\n  ! Could not create %s\n\n", "result-enc.txt" );
156         goto exit;
157     }
158 
159     for( i = 0; i < rsa.MBEDTLS_PRIVATE(len); i++ )
160         mbedtls_fprintf( f, "%02X%s", buf[i],
161                  ( i + 1 ) % 16 == 0 ? "\r\n" : " " );
162 
163     fclose( f );
164 
165     mbedtls_printf( "\n  . Done (created \"%s\")\n\n", "result-enc.txt" );
166 
167     exit_code = MBEDTLS_EXIT_SUCCESS;
168 
169 exit:
170     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &E );
171     mbedtls_ctr_drbg_free( &ctr_drbg );
172     mbedtls_entropy_free( &entropy );
173     mbedtls_rsa_free( &rsa );
174 
175 #if defined(_WIN32)
176     mbedtls_printf( "  + Press Enter to exit this program.\n" );
177     fflush( stdout ); getchar();
178 #endif
179 
180     mbedtls_exit( exit_code );
181 }
182 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_ENTROPY_C &&
183           MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
184