2 * RSA simple decryption program
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
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
11 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 * This file is part of mbed TLS (https://tls.mbed.org)
22 #if !defined(MBEDTLS_CONFIG_FILE)
23 #include "mbedtls/config.h"
25 #include MBEDTLS_CONFIG_FILE
28 #if defined(MBEDTLS_PLATFORM_C)
29 #include "mbedtls/platform.h"
33 #define mbedtls_printf printf
34 #define mbedtls_exit exit
35 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
36 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
37 #endif /* MBEDTLS_PLATFORM_C */
39 #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_RSA_C) && \
40 defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
41 defined(MBEDTLS_CTR_DRBG_C)
42 #include "mbedtls/rsa.h"
43 #include "mbedtls/entropy.h"
44 #include "mbedtls/ctr_drbg.h"
50 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) || \
51 !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_ENTROPY_C) || \
52 !defined(MBEDTLS_CTR_DRBG_C)
55 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
56 "MBEDTLS_FS_IO and/or MBEDTLS_ENTROPY_C and/or "
57 "MBEDTLS_CTR_DRBG_C not defined.\n");
62 #if defined(MBEDTLS_CHECK_PARAMS)
63 #include "mbedtls/platform_util.h"
64 void mbedtls_param_failed( const char *failure_condition,
68 mbedtls_printf( "%s:%i: Input param failed - %s\n",
69 file, line, failure_condition );
70 mbedtls_exit( MBEDTLS_EXIT_FAILURE );
74 int main( int argc, char *argv[] )
78 int exit_code = MBEDTLS_EXIT_FAILURE;
81 mbedtls_rsa_context rsa;
82 mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;
83 mbedtls_entropy_context entropy;
84 mbedtls_ctr_drbg_context ctr_drbg;
85 unsigned char result[1024];
86 unsigned char buf[512];
87 const char *pers = "rsa_decrypt";
90 memset(result, 0, sizeof( result ) );
94 mbedtls_printf( "usage: rsa_decrypt\n" );
97 mbedtls_printf( "\n" );
100 mbedtls_exit( exit_code );
103 mbedtls_printf( "\n . Seeding the random number generator..." );
106 mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
107 mbedtls_ctr_drbg_init( &ctr_drbg );
108 mbedtls_entropy_init( &entropy );
109 mbedtls_mpi_init( &N ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q );
110 mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
111 mbedtls_mpi_init( &DQ ); mbedtls_mpi_init( &QP );
113 ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
114 &entropy, (const unsigned char *) pers,
118 mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n",
123 mbedtls_printf( "\n . Reading private key from rsa_priv.txt" );
126 if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL )
128 mbedtls_printf( " failed\n ! Could not open rsa_priv.txt\n" \
129 " ! Please run rsa_genkey first\n\n" );
133 if( ( ret = mbedtls_mpi_read_file( &N , 16, f ) ) != 0 ||
134 ( ret = mbedtls_mpi_read_file( &E , 16, f ) ) != 0 ||
135 ( ret = mbedtls_mpi_read_file( &D , 16, f ) ) != 0 ||
136 ( ret = mbedtls_mpi_read_file( &P , 16, f ) ) != 0 ||
137 ( ret = mbedtls_mpi_read_file( &Q , 16, f ) ) != 0 ||
138 ( ret = mbedtls_mpi_read_file( &DP , 16, f ) ) != 0 ||
139 ( ret = mbedtls_mpi_read_file( &DQ , 16, f ) ) != 0 ||
140 ( ret = mbedtls_mpi_read_file( &QP , 16, f ) ) != 0 )
142 mbedtls_printf( " failed\n ! mbedtls_mpi_read_file returned %d\n\n",
149 if( ( ret = mbedtls_rsa_import( &rsa, &N, &P, &Q, &D, &E ) ) != 0 )
151 mbedtls_printf( " failed\n ! mbedtls_rsa_import returned %d\n\n",
156 if( ( ret = mbedtls_rsa_complete( &rsa ) ) != 0 )
158 mbedtls_printf( " failed\n ! mbedtls_rsa_complete returned %d\n\n",
164 * Extract the RSA encrypted value from the text file
166 if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL )
168 mbedtls_printf( "\n ! Could not open %s\n\n", "result-enc.txt" );
174 while( fscanf( f, "%02X", &c ) > 0 &&
175 i < (int) sizeof( buf ) )
176 buf[i++] = (unsigned char) c;
182 mbedtls_printf( "\n ! Invalid RSA signature format\n\n" );
187 * Decrypt the encrypted RSA data and print the result.
189 mbedtls_printf( "\n . Decrypting the encrypted data" );
192 ret = mbedtls_rsa_pkcs1_decrypt( &rsa, mbedtls_ctr_drbg_random,
193 &ctr_drbg, MBEDTLS_RSA_PRIVATE, &i,
197 mbedtls_printf( " failed\n ! mbedtls_rsa_pkcs1_decrypt returned %d\n\n",
202 mbedtls_printf( "\n . OK\n\n" );
204 mbedtls_printf( "The decrypted result is: '%s'\n\n", result );
206 exit_code = MBEDTLS_EXIT_SUCCESS;
209 mbedtls_ctr_drbg_free( &ctr_drbg );
210 mbedtls_entropy_free( &entropy );
211 mbedtls_rsa_free( &rsa );
212 mbedtls_mpi_free( &N ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
213 mbedtls_mpi_free( &D ); mbedtls_mpi_free( &E ); mbedtls_mpi_free( &DP );
214 mbedtls_mpi_free( &DQ ); mbedtls_mpi_free( &QP );
217 mbedtls_printf( " + Press Enter to exit this program.\n" );
218 fflush( stdout ); getchar();
223 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_FS_IO */