rsa_verify.c 4.0 KB

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  1. /*
  2. * RSA/SHA-1 signature verification program
  3. *
  4. * Copyright (C) 2006-2010, Brainspark B.V.
  5. *
  6. * This file is part of PolarSSL (http://www.polarssl.org)
  7. * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
  8. *
  9. * All rights reserved.
  10. *
  11. * This program is free software; you can redistribute it and/or modify
  12. * it under the terms of the GNU General Public License as published by
  13. * the Free Software Foundation; either version 2 of the License, or
  14. * (at your option) any later version.
  15. *
  16. * This program is distributed in the hope that it will be useful,
  17. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19. * GNU General Public License for more details.
  20. *
  21. * You should have received a copy of the GNU General Public License along
  22. * with this program; if not, write to the Free Software Foundation, Inc.,
  23. * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24. */
  25. #ifndef _CRT_SECURE_NO_DEPRECATE
  26. #define _CRT_SECURE_NO_DEPRECATE 1
  27. #endif
  28. #include <string.h>
  29. #include <stdio.h>
  30. #include "polarssl/config.h"
  31. #include "polarssl/rsa.h"
  32. #include "polarssl/sha1.h"
  33. #if !defined(POLARSSL_BIGNUM_C) || !defined(POLARSSL_RSA_C) || \
  34. !defined(POLARSSL_SHA1_C) || !defined(POLARSSL_FS_IO)
  35. int main( void )
  36. {
  37. printf("POLARSSL_BIGNUM_C and/or POLARSSL_RSA_C and/or "
  38. "POLARSSL_SHA1_C and/or POLARSSL_FS_IO not defined.\n");
  39. return( 0 );
  40. }
  41. #else
  42. int main( int argc, char *argv[] )
  43. {
  44. FILE *f;
  45. int ret, c;
  46. size_t i;
  47. rsa_context rsa;
  48. unsigned char hash[20];
  49. unsigned char buf[512];
  50. ret = 1;
  51. if( argc != 2 )
  52. {
  53. printf( "usage: rsa_verify <filename>\n" );
  54. #ifdef WIN32
  55. printf( "\n" );
  56. #endif
  57. goto exit;
  58. }
  59. printf( "\n . Reading public key from rsa_pub.txt" );
  60. fflush( stdout );
  61. if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
  62. {
  63. printf( " failed\n ! Could not open rsa_pub.txt\n" \
  64. " ! Please run rsa_genkey first\n\n" );
  65. goto exit;
  66. }
  67. rsa_init( &rsa, RSA_PKCS_V15, 0 );
  68. if( ( ret = mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
  69. ( ret = mpi_read_file( &rsa.E, 16, f ) ) != 0 )
  70. {
  71. printf( " failed\n ! mpi_read_file returned %d\n\n", ret );
  72. goto exit;
  73. }
  74. rsa.len = ( mpi_msb( &rsa.N ) + 7 ) >> 3;
  75. fclose( f );
  76. /*
  77. * Extract the RSA signature from the text file
  78. */
  79. ret = 1;
  80. i = strlen( argv[1] );
  81. memcpy( argv[1] + i, ".sig", 5 );
  82. if( ( f = fopen( argv[1], "rb" ) ) == NULL )
  83. {
  84. printf( "\n ! Could not open %s\n\n", argv[1] );
  85. goto exit;
  86. }
  87. argv[1][i] = '\0', i = 0;
  88. while( fscanf( f, "%02X", &c ) > 0 &&
  89. i < (int) sizeof( buf ) )
  90. buf[i++] = (unsigned char) c;
  91. fclose( f );
  92. if( i != rsa.len )
  93. {
  94. printf( "\n ! Invalid RSA signature format\n\n" );
  95. goto exit;
  96. }
  97. /*
  98. * Compute the SHA-1 hash of the input file and compare
  99. * it with the hash decrypted from the RSA signature.
  100. */
  101. printf( "\n . Verifying the RSA/SHA-1 signature" );
  102. fflush( stdout );
  103. if( ( ret = sha1_file( argv[1], hash ) ) != 0 )
  104. {
  105. printf( " failed\n ! Could not open or read %s\n\n", argv[1] );
  106. goto exit;
  107. }
  108. if( ( ret = rsa_pkcs1_verify( &rsa, RSA_PUBLIC, SIG_RSA_SHA1,
  109. 20, hash, buf ) ) != 0 )
  110. {
  111. printf( " failed\n ! rsa_pkcs1_verify returned %d\n\n", ret );
  112. goto exit;
  113. }
  114. printf( "\n . OK (the decrypted SHA-1 hash matches)\n\n" );
  115. ret = 0;
  116. exit:
  117. #ifdef WIN32
  118. printf( " + Press Enter to exit this program.\n" );
  119. fflush( stdout ); getchar();
  120. #endif
  121. return( ret );
  122. }
  123. #endif /* POLARSSL_BIGNUM_C && POLARSSL_RSA_C && POLARSSL_SHA1_C &&
  124. POLARSSL_FS_IO */