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/*
* RSA simple decryption program
*
* Copyright (C) 2006-2011, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE 1
#endif
#include <string.h>
#include <stdio.h>
#include "polarssl/config.h"
#include "polarssl/rsa.h"
#if !defined(POLARSSL_BIGNUM_C) || !defined(POLARSSL_RSA_C) || \
!defined(POLARSSL_FS_IO)
int main( int argc, char *argv[] )
{
((void) argc);
((void) argv);
printf("POLARSSL_BIGNUM_C and/or POLARSSL_RSA_C and/or "
"POLARSSL_FS_IO not defined.\n");
return( 0 );
}
#else
int main( int argc, char *argv[] )
{
FILE *f;
int ret, c;
size_t i;
rsa_context rsa;
unsigned char result[1024];
unsigned char buf[512];
((void) argv);
memset(result, 0, sizeof( result ) );
ret = 1;
if( argc != 1 )
{
printf( "usage: rsa_decrypt\n" );
#if defined(_WIN32)
printf( "\n" );
#endif
goto exit;
}
printf( "\n . Reading private key from rsa_priv.txt" );
fflush( stdout );
if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL )
{
printf( " failed\n ! Could not open rsa_priv.txt\n" \
" ! Please run rsa_genkey first\n\n" );
goto exit;
}
rsa_init( &rsa, RSA_PKCS_V15, 0 );
if( ( ret = mpi_read_file( &rsa.N , 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.E , 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.D , 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.P , 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.Q , 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.DP, 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.DQ, 16, f ) ) != 0 ||
( ret = mpi_read_file( &rsa.QP, 16, f ) ) != 0 )
{
printf( " failed\n ! mpi_read_file returned %d\n\n", ret );
goto exit;
}
rsa.len = ( mpi_msb( &rsa.N ) + 7 ) >> 3;
fclose( f );
/*
* Extract the RSA encrypted value from the text file
*/
ret = 1;
if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL )
{
printf( "\n ! Could not open %s\n\n", "result-enc.txt" );
goto exit;
}
i = 0;
while( fscanf( f, "%02X", &c ) > 0 &&
i < (int) sizeof( buf ) )
buf[i++] = (unsigned char) c;
fclose( f );
if( i != rsa.len )
{
printf( "\n ! Invalid RSA signature format\n\n" );
goto exit;
}
/*
* Decrypt the encrypted RSA data and print the result.
*/
printf( "\n . Decrypting the encrypted data" );
fflush( stdout );
if( ( ret = rsa_pkcs1_decrypt( &rsa, RSA_PRIVATE, &i, buf, result,
1024 ) ) != 0 )
{
printf( " failed\n ! rsa_pkcs1_decrypt returned %d\n\n", ret );
goto exit;
}
printf( "\n . OK\n\n" );
printf( "The decrypted result is: '%s'\n\n", result );
ret = 0;
exit:
#if defined(_WIN32)
printf( " + Press Enter to exit this program.\n" );
fflush( stdout ); getchar();
#endif
return( ret );
}
#endif /* POLARSSL_BIGNUM_C && POLARSSL_RSA_C && POLARSSL_FS_IO */