programs/aes/crypt_and_hash.c - third_party/github/ARMmbed/mbedtls - Git at Google

 /*
  *  \brief  Generic file encryption program using generic wrappers for configured
  *          security.
  *
  *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  *  not use this file except in compliance with the License.
  *  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  */

 /* Enable definition of fileno() even when compiling with -std=c99. Must be
  * set before config.h, which pulls in glibc's features.h indirectly.
  * Harmless on other platforms. */
 #define _POSIX_C_SOURCE 1

 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
 #else
 #include MBEDTLS_CONFIG_FILE
 #endif

 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
 #include <stdlib.h>
 #define mbedtls_fprintf         fprintf
 #define mbedtls_printf          printf
 #define mbedtls_exit            exit
 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
 #endif /* MBEDTLS_PLATFORM_C */

 #if defined(MBEDTLS_CIPHER_C) && defined(MBEDTLS_MD_C) && \
  defined(MBEDTLS_FS_IO)
 #include "mbedtls/cipher.h"
 #include "mbedtls/md.h"
 #include "mbedtls/platform_util.h"

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #endif

 #if defined(_WIN32)
 #include <windows.h>
 #if !defined(_WIN32_WCE)
 #include <io.h>
 #endif
 #else
 #include <sys/types.h>
 #include <unistd.h>
 #endif

 #define MODE_ENCRYPT    0
 #define MODE_DECRYPT    1

 #define USAGE   \
     "\n  crypt_and_hash <mode> <input filename> <output filename> <cipher> <mbedtls_md> <key>\n" \
     "\n   <mode>: 0 = encrypt, 1 = decrypt\n" \
     "\n  example: crypt_and_hash 0 file file.aes AES-128-CBC SHA1 hex:E76B2413958B00E193\n" \
     "\n"

 #if !defined(MBEDTLS_CIPHER_C) || !defined(MBEDTLS_MD_C) || \
     !defined(MBEDTLS_FS_IO)
 int main( void )
 {
     mbedtls_printf("MBEDTLS_CIPHER_C and/or MBEDTLS_MD_C and/or MBEDTLS_FS_IO not defined.\n");
     return( 0 );
 }
 #else


 int main( int argc, char *argv[] )
 {
     int ret = 1, i, n;
     int exit_code = MBEDTLS_EXIT_FAILURE;
     int mode;
     size_t keylen, ilen, olen;
     FILE *fkey, *fin = NULL, *fout = NULL;

     char *p;
     unsigned char IV[16];
     unsigned char key[512];
     unsigned char digest[MBEDTLS_MD_MAX_SIZE];
     unsigned char buffer[1024];
     unsigned char output[1024];
     unsigned char diff;

     const mbedtls_cipher_info_t *cipher_info;
     const mbedtls_md_info_t *md_info;
     mbedtls_cipher_context_t cipher_ctx;
     mbedtls_md_context_t md_ctx;
 #if defined(_WIN32_WCE)
     long filesize, offset;
 #elif defined(_WIN32)
        LARGE_INTEGER li_size;
     __int64 filesize, offset;
 #else
       off_t filesize, offset;
 #endif

     mbedtls_cipher_init( &cipher_ctx );
     mbedtls_md_init( &md_ctx );

     /*
      * Parse the command-line arguments.
      */
     if( argc != 7 )
     {
         const int *list;

         mbedtls_printf( USAGE );

         mbedtls_printf( "Available ciphers:\n" );
         list = mbedtls_cipher_list();
         while( *list )
         {
             cipher_info = mbedtls_cipher_info_from_type( *list );
             mbedtls_printf( "  %s\n", cipher_info->name );
             list++;
         }

         mbedtls_printf( "\nAvailable message digests:\n" );
         list = mbedtls_md_list();
         while( *list )
         {
             md_info = mbedtls_md_info_from_type( *list );
             mbedtls_printf( "  %s\n", mbedtls_md_get_name( md_info ) );
             list++;
         }

 #if defined(_WIN32)
         mbedtls_printf( "\n  Press Enter to exit this program.\n" );
         fflush( stdout ); getchar();
 #endif

         goto exit;
     }

     mode = atoi( argv[1] );

     if( mode != MODE_ENCRYPT && mode != MODE_DECRYPT )
     {
         mbedtls_fprintf( stderr, "invalid operation mode\n" );
         goto exit;
     }

     if( strcmp( argv[2], argv[3] ) == 0 )
     {
         mbedtls_fprintf( stderr, "input and output filenames must differ\n" );
         goto exit;
     }

     if( ( fin = fopen( argv[2], "rb" ) ) == NULL )
     {
         mbedtls_fprintf( stderr, "fopen(%s,rb) failed\n", argv[2] );
         goto exit;
     }

     if( ( fout = fopen( argv[3], "wb+" ) ) == NULL )
     {
         mbedtls_fprintf( stderr, "fopen(%s,wb+) failed\n", argv[3] );
         goto exit;
     }

     /*
      * Read the Cipher and MD from the command line
      */
     cipher_info = mbedtls_cipher_info_from_string( argv[4] );
     if( cipher_info == NULL )
     {
         mbedtls_fprintf( stderr, "Cipher '%s' not found\n", argv[4] );
         goto exit;
     }
     if( ( ret = mbedtls_cipher_setup( &cipher_ctx, cipher_info) ) != 0 )
     {
         mbedtls_fprintf( stderr, "mbedtls_cipher_setup failed\n" );
         goto exit;
     }

     md_info = mbedtls_md_info_from_string( argv[5] );
     if( md_info == NULL )
     {
         mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[5] );
         goto exit;
     }

     if( mbedtls_md_setup( &md_ctx, md_info, 1 ) != 0 )
     {
         mbedtls_fprintf( stderr, "mbedtls_md_setup failed\n" );
         goto exit;
     }

     /*
      * Read the secret key from file or command line
      */
     if( ( fkey = fopen( argv[6], "rb" ) ) != NULL )
     {
         keylen = fread( key, 1, sizeof( key ), fkey );
         fclose( fkey );
     }
     else
     {
         if( memcmp( argv[6], "hex:", 4 ) == 0 )
         {
             p = &argv[6][4];
             keylen = 0;

             while( sscanf( p, "%02X", &n ) > 0 &&
                    keylen < (int) sizeof( key ) )
             {
                 key[keylen++] = (unsigned char) n;
                 p += 2;
             }
         }
         else
         {
             keylen = strlen( argv[6] );

             if( keylen > (int) sizeof( key ) )
                 keylen = (int) sizeof( key );

             memcpy( key, argv[6], keylen );
         }
     }

 #if defined(_WIN32_WCE)
     filesize = fseek( fin, 0L, SEEK_END );
 #else
 #if defined(_WIN32)
     /*
      * Support large files (> 2Gb) on Win32
      */
     li_size.QuadPart = 0;
     li_size.LowPart  =
         SetFilePointer( (HANDLE) _get_osfhandle( _fileno( fin ) ),
                         li_size.LowPart, &li_size.HighPart, FILE_END );

     if( li_size.LowPart == 0xFFFFFFFF && GetLastError() != NO_ERROR )
     {
         mbedtls_fprintf( stderr, "SetFilePointer(0,FILE_END) failed\n" );
         goto exit;
     }

     filesize = li_size.QuadPart;
 #else
     if( ( filesize = lseek( fileno( fin ), 0, SEEK_END ) ) < 0 )
     {
         perror( "lseek" );
         goto exit;
     }
 #endif
 #endif

     if( fseek( fin, 0, SEEK_SET ) < 0 )
     {
         mbedtls_fprintf( stderr, "fseek(0,SEEK_SET) failed\n" );
         goto exit;
     }

     if( mode == MODE_ENCRYPT )
     {
         /*
          * Generate the initialization vector as:
          * IV = MD( filesize || filename )[0..15]
          */
         for( i = 0; i < 8; i++ )
             buffer[i] = (unsigned char)( filesize >> ( i << 3 ) );

         p = argv[2];

         mbedtls_md_starts( &md_ctx );
         mbedtls_md_update( &md_ctx, buffer, 8 );
         mbedtls_md_update( &md_ctx, (unsigned char *) p, strlen( p ) );
         mbedtls_md_finish( &md_ctx, digest );

         memcpy( IV, digest, 16 );

         /*
          * Append the IV at the beginning of the output.
          */
         if( fwrite( IV, 1, 16, fout ) != 16 )
         {
             mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", 16 );
             goto exit;
         }

         /*
          * Hash the IV and the secret key together 8192 times
          * using the result to setup the AES context and HMAC.
          */
         memset( digest, 0,  32 );
         memcpy( digest, IV, 16 );

         for( i = 0; i < 8192; i++ )
         {
             mbedtls_md_starts( &md_ctx );
             mbedtls_md_update( &md_ctx, digest, 32 );
             mbedtls_md_update( &md_ctx, key, keylen );
             mbedtls_md_finish( &md_ctx, digest );

         }

         if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
                            MBEDTLS_ENCRYPT ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n");
             goto exit;
         }
         if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n");
             goto exit;
         }
         if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n");
             goto exit;
         }

         mbedtls_md_hmac_starts( &md_ctx, digest, 32 );

         /*
          * Encrypt and write the ciphertext.
          */
         for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
         {
             ilen = ( (unsigned int) filesize - offset > mbedtls_cipher_get_block_size( &cipher_ctx ) ) ?
                 mbedtls_cipher_get_block_size( &cipher_ctx ) : (unsigned int) ( filesize - offset );

             if( fread( buffer, 1, ilen, fin ) != ilen )
             {
                 mbedtls_fprintf( stderr, "fread(%ld bytes) failed\n", (long) ilen );
                 goto exit;
             }

             if( mbedtls_cipher_update( &cipher_ctx, buffer, ilen, output, &olen ) != 0 )
             {
                 mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n");
                 goto exit;
             }

             mbedtls_md_hmac_update( &md_ctx, output, olen );

             if( fwrite( output, 1, olen, fout ) != olen )
             {
                 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
                 goto exit;
             }
         }

         if( mbedtls_cipher_finish( &cipher_ctx, output, &olen ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_finish() returned error\n" );
             goto exit;
         }
         mbedtls_md_hmac_update( &md_ctx, output, olen );

         if( fwrite( output, 1, olen, fout ) != olen )
         {
             mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
             goto exit;
         }

         /*
          * Finally write the HMAC.
          */
         mbedtls_md_hmac_finish( &md_ctx, digest );

         if( fwrite( digest, 1, mbedtls_md_get_size( md_info ), fout ) != mbedtls_md_get_size( md_info ) )
         {
             mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
             goto exit;
         }
     }

     if( mode == MODE_DECRYPT )
     {
         /*
          *  The encrypted file must be structured as follows:
          *
          *        00 .. 15              Initialization Vector
          *        16 .. 31              Encrypted Block #1
          *           ..
          *      N*16 .. (N+1)*16 - 1    Encrypted Block #N
          *  (N+1)*16 .. (N+1)*16 + n    Hash(ciphertext)
          */
         if( filesize < 16 + mbedtls_md_get_size( md_info ) )
         {
             mbedtls_fprintf( stderr, "File too short to be encrypted.\n" );
             goto exit;
         }

         if( mbedtls_cipher_get_block_size( &cipher_ctx ) == 0 )
         {
             mbedtls_fprintf( stderr, "Invalid cipher block size: 0. \n" );
             goto exit;
         }

         /*
          * Check the file size.
          */
         if( cipher_info->mode != MBEDTLS_MODE_GCM &&
             ( ( filesize - mbedtls_md_get_size( md_info ) ) %
                 mbedtls_cipher_get_block_size( &cipher_ctx ) ) != 0 )
         {
             mbedtls_fprintf( stderr, "File content not a multiple of the block size (%d).\n",
                      mbedtls_cipher_get_block_size( &cipher_ctx ));
             goto exit;
         }

         /*
          * Subtract the IV + HMAC length.
          */
         filesize -= ( 16 + mbedtls_md_get_size( md_info ) );

         /*
          * Read the IV and original filesize modulo 16.
          */
         if( fread( buffer, 1, 16, fin ) != 16 )
         {
             mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", 16 );
             goto exit;
         }

         memcpy( IV, buffer, 16 );

         /*
          * Hash the IV and the secret key together 8192 times
          * using the result to setup the AES context and HMAC.
          */
         memset( digest, 0,  32 );
         memcpy( digest, IV, 16 );

         for( i = 0; i < 8192; i++ )
         {
             mbedtls_md_starts( &md_ctx );
             mbedtls_md_update( &md_ctx, digest, 32 );
             mbedtls_md_update( &md_ctx, key, keylen );
             mbedtls_md_finish( &md_ctx, digest );
         }

         if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
                            MBEDTLS_DECRYPT ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n" );
             goto exit;
         }

         if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n" );
             goto exit;
         }

         if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
         {
             mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n" );
             goto exit;
         }

         mbedtls_md_hmac_starts( &md_ctx, digest, 32 );

         /*
          * Decrypt and write the plaintext.
          */
         for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
         {
             ilen = ( (unsigned int) filesize - offset > mbedtls_cipher_get_block_size( &cipher_ctx ) ) ?
                 mbedtls_cipher_get_block_size( &cipher_ctx ) : (unsigned int) ( filesize - offset );

             if( fread( buffer, 1, ilen, fin ) != ilen )
             {
                 mbedtls_fprintf( stderr, "fread(%d bytes) failed\n",
                     mbedtls_cipher_get_block_size( &cipher_ctx ) );
                 goto exit;
             }

             mbedtls_md_hmac_update( &md_ctx, buffer, ilen );
             if( mbedtls_cipher_update( &cipher_ctx, buffer, ilen, output,
                                        &olen ) != 0 )
             {
                 mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n" );
                 goto exit;
             }

             if( fwrite( output, 1, olen, fout ) != olen )
             {
                 mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
                 goto exit;
             }
         }

         /*
          * Verify the message authentication code.
          */
         mbedtls_md_hmac_finish( &md_ctx, digest );

         if( fread( buffer, 1, mbedtls_md_get_size( md_info ), fin ) != mbedtls_md_get_size( md_info ) )
         {
             mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
             goto exit;
         }

         /* Use constant-time buffer comparison */
         diff = 0;
         for( i = 0; i < mbedtls_md_get_size( md_info ); i++ )
             diff |= digest[i] ^ buffer[i];

         if( diff != 0 )
         {
             mbedtls_fprintf( stderr, "HMAC check failed: wrong key, "
                              "or file corrupted.\n" );
             goto exit;
         }

         /*
          * Write the final block of data
          */
         mbedtls_cipher_finish( &cipher_ctx, output, &olen );

         if( fwrite( output, 1, olen, fout ) != olen )
         {
             mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
             goto exit;
         }
     }

     exit_code = MBEDTLS_EXIT_SUCCESS;

 exit:
     if( fin )
         fclose( fin );
     if( fout )
         fclose( fout );

     /* Zeroize all command line arguments to also cover
        the case when the user has missed or reordered some,
        in which case the key might not be in argv[6]. */
     for( i = 0; i < argc; i++ )
         mbedtls_platform_zeroize( argv[i], strlen( argv[i] ) );

     mbedtls_platform_zeroize( IV,     sizeof( IV ) );
     mbedtls_platform_zeroize( key,    sizeof( key ) );
     mbedtls_platform_zeroize( buffer, sizeof( buffer ) );
     mbedtls_platform_zeroize( output, sizeof( output ) );
     mbedtls_platform_zeroize( digest, sizeof( digest ) );

     mbedtls_cipher_free( &cipher_ctx );
     mbedtls_md_free( &md_ctx );

     return( exit_code );
 }
 #endif /* MBEDTLS_CIPHER_C && MBEDTLS_MD_C && MBEDTLS_FS_IO */
	/*
	* \brief Generic file encryption program using generic wrappers for configured
	* security.
	*
	* Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
	* SPDX-License-Identifier: Apache-2.0
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may
	* not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	* This file is part of mbed TLS (https://tls.mbed.org)
	*/

	/* Enable definition of fileno() even when compiling with -std=c99. Must be
	* set before config.h, which pulls in glibc's features.h indirectly.
	* Harmless on other platforms. */
	#define _POSIX_C_SOURCE 1

	#if !defined(MBEDTLS_CONFIG_FILE)
	#include "mbedtls/config.h"
	#else
	#include MBEDTLS_CONFIG_FILE
	#endif

	#if defined(MBEDTLS_PLATFORM_C)
	#include "mbedtls/platform.h"
	#else
	#include <stdio.h>
	#include <stdlib.h>
	#define mbedtls_fprintf fprintf
	#define mbedtls_printf printf
	#define mbedtls_exit exit
	#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
	#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
	#endif /* MBEDTLS_PLATFORM_C */

	#if defined(MBEDTLS_CIPHER_C) && defined(MBEDTLS_MD_C) && \
	defined(MBEDTLS_FS_IO)
	#include "mbedtls/cipher.h"
	#include "mbedtls/md.h"
	#include "mbedtls/platform_util.h"

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#endif

	#if defined(_WIN32)
	#include <windows.h>
	#if !defined(_WIN32_WCE)
	#include <io.h>
	#endif
	#else
	#include <sys/types.h>
	#include <unistd.h>
	#endif

	#define MODE_ENCRYPT 0
	#define MODE_DECRYPT 1

	#define USAGE \
	"\n crypt_and_hash <mode> <input filename> <output filename> <cipher> <mbedtls_md> <key>\n" \
	"\n <mode>: 0 = encrypt, 1 = decrypt\n" \
	"\n example: crypt_and_hash 0 file file.aes AES-128-CBC SHA1 hex:E76B2413958B00E193\n" \
	"\n"

	#if !defined(MBEDTLS_CIPHER_C) \|\| !defined(MBEDTLS_MD_C) \|\| \
	!defined(MBEDTLS_FS_IO)
	int main( void )
	{
	mbedtls_printf("MBEDTLS_CIPHER_C and/or MBEDTLS_MD_C and/or MBEDTLS_FS_IO not defined.\n");
	return( 0 );
	}
	#else


	int main( int argc, char *argv[] )
	{
	int ret = 1, i, n;
	int exit_code = MBEDTLS_EXIT_FAILURE;
	int mode;
	size_t keylen, ilen, olen;
	FILE fkey, fin = NULL, *fout = NULL;

	char *p;
	unsigned char IV[16];
	unsigned char key[512];
	unsigned char digest[MBEDTLS_MD_MAX_SIZE];
	unsigned char buffer[1024];
	unsigned char output[1024];
	unsigned char diff;

	const mbedtls_cipher_info_t *cipher_info;
	const mbedtls_md_info_t *md_info;
	mbedtls_cipher_context_t cipher_ctx;
	mbedtls_md_context_t md_ctx;
	#if defined(_WIN32_WCE)
	long filesize, offset;
	#elif defined(_WIN32)
	LARGE_INTEGER li_size;
	__int64 filesize, offset;
	#else
	off_t filesize, offset;
	#endif

	mbedtls_cipher_init( &cipher_ctx );
	mbedtls_md_init( &md_ctx );

	/*
	* Parse the command-line arguments.
	*/
	if( argc != 7 )
	{
	const int *list;

	mbedtls_printf( USAGE );

	mbedtls_printf( "Available ciphers:\n" );
	list = mbedtls_cipher_list();
	while( *list )
	{
	cipher_info = mbedtls_cipher_info_from_type( *list );
	mbedtls_printf( " %s\n", cipher_info->name );
	list++;
	}

	mbedtls_printf( "\nAvailable message digests:\n" );
	list = mbedtls_md_list();
	while( *list )
	{
	md_info = mbedtls_md_info_from_type( *list );
	mbedtls_printf( " %s\n", mbedtls_md_get_name( md_info ) );
	list++;
	}

	#if defined(_WIN32)
	mbedtls_printf( "\n Press Enter to exit this program.\n" );
	fflush( stdout ); getchar();
	#endif

	goto exit;
	}

	mode = atoi( argv[1] );

	if( mode != MODE_ENCRYPT && mode != MODE_DECRYPT )
	{
	mbedtls_fprintf( stderr, "invalid operation mode\n" );
	goto exit;
	}

	if( strcmp( argv[2], argv[3] ) == 0 )
	{
	mbedtls_fprintf( stderr, "input and output filenames must differ\n" );
	goto exit;
	}

	if( ( fin = fopen( argv[2], "rb" ) ) == NULL )
	{
	mbedtls_fprintf( stderr, "fopen(%s,rb) failed\n", argv[2] );
	goto exit;
	}

	if( ( fout = fopen( argv[3], "wb+" ) ) == NULL )
	{
	mbedtls_fprintf( stderr, "fopen(%s,wb+) failed\n", argv[3] );
	goto exit;
	}

	/*
	* Read the Cipher and MD from the command line
	*/
	cipher_info = mbedtls_cipher_info_from_string( argv[4] );
	if( cipher_info == NULL )
	{
	mbedtls_fprintf( stderr, "Cipher '%s' not found\n", argv[4] );
	goto exit;
	}
	if( ( ret = mbedtls_cipher_setup( &cipher_ctx, cipher_info) ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_setup failed\n" );
	goto exit;
	}

	md_info = mbedtls_md_info_from_string( argv[5] );
	if( md_info == NULL )
	{
	mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[5] );
	goto exit;
	}

	if( mbedtls_md_setup( &md_ctx, md_info, 1 ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_md_setup failed\n" );
	goto exit;
	}

	/*
	* Read the secret key from file or command line
	*/
	if( ( fkey = fopen( argv[6], "rb" ) ) != NULL )
	{
	keylen = fread( key, 1, sizeof( key ), fkey );
	fclose( fkey );
	}
	else
	{
	if( memcmp( argv[6], "hex:", 4 ) == 0 )
	{
	p = &argv[6][4];
	keylen = 0;

	while( sscanf( p, "%02X", &n ) > 0 &&
	keylen < (int) sizeof( key ) )
	{
	key[keylen++] = (unsigned char) n;
	p += 2;
	}
	}
	else
	{
	keylen = strlen( argv[6] );

	if( keylen > (int) sizeof( key ) )
	keylen = (int) sizeof( key );

	memcpy( key, argv[6], keylen );
	}
	}

	#if defined(_WIN32_WCE)
	filesize = fseek( fin, 0L, SEEK_END );
	#else
	#if defined(_WIN32)
	/*
	* Support large files (> 2Gb) on Win32
	*/
	li_size.QuadPart = 0;
	li_size.LowPart =
	SetFilePointer( (HANDLE) _get_osfhandle( _fileno( fin ) ),
	li_size.LowPart, &li_size.HighPart, FILE_END );

	if( li_size.LowPart == 0xFFFFFFFF && GetLastError() != NO_ERROR )
	{
	mbedtls_fprintf( stderr, "SetFilePointer(0,FILE_END) failed\n" );
	goto exit;
	}

	filesize = li_size.QuadPart;
	#else
	if( ( filesize = lseek( fileno( fin ), 0, SEEK_END ) ) < 0 )
	{
	perror( "lseek" );
	goto exit;
	}
	#endif
	#endif

	if( fseek( fin, 0, SEEK_SET ) < 0 )
	{
	mbedtls_fprintf( stderr, "fseek(0,SEEK_SET) failed\n" );
	goto exit;
	}

	if( mode == MODE_ENCRYPT )
	{
	/*
	* Generate the initialization vector as:
	* IV = MD( filesize \|\| filename )[0..15]
	*/
	for( i = 0; i < 8; i++ )
	buffer[i] = (unsigned char)( filesize >> ( i << 3 ) );

	p = argv[2];

	mbedtls_md_starts( &md_ctx );
	mbedtls_md_update( &md_ctx, buffer, 8 );
	mbedtls_md_update( &md_ctx, (unsigned char *) p, strlen( p ) );
	mbedtls_md_finish( &md_ctx, digest );

	memcpy( IV, digest, 16 );

	/*
	* Append the IV at the beginning of the output.
	*/
	if( fwrite( IV, 1, 16, fout ) != 16 )
	{
	mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", 16 );
	goto exit;
	}

	/*
	* Hash the IV and the secret key together 8192 times
	* using the result to setup the AES context and HMAC.
	*/
	memset( digest, 0, 32 );
	memcpy( digest, IV, 16 );

	for( i = 0; i < 8192; i++ )
	{
	mbedtls_md_starts( &md_ctx );
	mbedtls_md_update( &md_ctx, digest, 32 );
	mbedtls_md_update( &md_ctx, key, keylen );
	mbedtls_md_finish( &md_ctx, digest );

	}

	if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
	MBEDTLS_ENCRYPT ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n");
	goto exit;
	}
	if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n");
	goto exit;
	}
	if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n");
	goto exit;
	}

	mbedtls_md_hmac_starts( &md_ctx, digest, 32 );

	/*
	* Encrypt and write the ciphertext.
	*/
	for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
	{
	ilen = ( (unsigned int) filesize - offset > mbedtls_cipher_get_block_size( &cipher_ctx ) ) ?
	mbedtls_cipher_get_block_size( &cipher_ctx ) : (unsigned int) ( filesize - offset );

	if( fread( buffer, 1, ilen, fin ) != ilen )
	{
	mbedtls_fprintf( stderr, "fread(%ld bytes) failed\n", (long) ilen );
	goto exit;
	}

	if( mbedtls_cipher_update( &cipher_ctx, buffer, ilen, output, &olen ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n");
	goto exit;
	}

	mbedtls_md_hmac_update( &md_ctx, output, olen );

	if( fwrite( output, 1, olen, fout ) != olen )
	{
	mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
	goto exit;
	}
	}

	if( mbedtls_cipher_finish( &cipher_ctx, output, &olen ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_finish() returned error\n" );
	goto exit;
	}
	mbedtls_md_hmac_update( &md_ctx, output, olen );

	if( fwrite( output, 1, olen, fout ) != olen )
	{
	mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
	goto exit;
	}

	/*
	* Finally write the HMAC.
	*/
	mbedtls_md_hmac_finish( &md_ctx, digest );

	if( fwrite( digest, 1, mbedtls_md_get_size( md_info ), fout ) != mbedtls_md_get_size( md_info ) )
	{
	mbedtls_fprintf( stderr, "fwrite(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
	goto exit;
	}
	}

	if( mode == MODE_DECRYPT )
	{
	/*
	* The encrypted file must be structured as follows:
	*
	* 00 .. 15 Initialization Vector
	* 16 .. 31 Encrypted Block #1
	* ..
	* N16 .. (N+1)16 - 1 Encrypted Block #N
	* (N+1)16 .. (N+1)16 + n Hash(ciphertext)
	*/
	if( filesize < 16 + mbedtls_md_get_size( md_info ) )
	{
	mbedtls_fprintf( stderr, "File too short to be encrypted.\n" );
	goto exit;
	}

	if( mbedtls_cipher_get_block_size( &cipher_ctx ) == 0 )
	{
	mbedtls_fprintf( stderr, "Invalid cipher block size: 0. \n" );
	goto exit;
	}

	/*
	* Check the file size.
	*/
	if( cipher_info->mode != MBEDTLS_MODE_GCM &&
	( ( filesize - mbedtls_md_get_size( md_info ) ) %
	mbedtls_cipher_get_block_size( &cipher_ctx ) ) != 0 )
	{
	mbedtls_fprintf( stderr, "File content not a multiple of the block size (%d).\n",
	mbedtls_cipher_get_block_size( &cipher_ctx ));
	goto exit;
	}

	/*
	* Subtract the IV + HMAC length.
	*/
	filesize -= ( 16 + mbedtls_md_get_size( md_info ) );

	/*
	* Read the IV and original filesize modulo 16.
	*/
	if( fread( buffer, 1, 16, fin ) != 16 )
	{
	mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", 16 );
	goto exit;
	}

	memcpy( IV, buffer, 16 );

	/*
	* Hash the IV and the secret key together 8192 times
	* using the result to setup the AES context and HMAC.
	*/
	memset( digest, 0, 32 );
	memcpy( digest, IV, 16 );

	for( i = 0; i < 8192; i++ )
	{
	mbedtls_md_starts( &md_ctx );
	mbedtls_md_update( &md_ctx, digest, 32 );
	mbedtls_md_update( &md_ctx, key, keylen );
	mbedtls_md_finish( &md_ctx, digest );
	}

	if( mbedtls_cipher_setkey( &cipher_ctx, digest, cipher_info->key_bitlen,
	MBEDTLS_DECRYPT ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_setkey() returned error\n" );
	goto exit;
	}

	if( mbedtls_cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_set_iv() returned error\n" );
	goto exit;
	}

	if( mbedtls_cipher_reset( &cipher_ctx ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_reset() returned error\n" );
	goto exit;
	}

	mbedtls_md_hmac_starts( &md_ctx, digest, 32 );

	/*
	* Decrypt and write the plaintext.
	*/
	for( offset = 0; offset < filesize; offset += mbedtls_cipher_get_block_size( &cipher_ctx ) )
	{
	ilen = ( (unsigned int) filesize - offset > mbedtls_cipher_get_block_size( &cipher_ctx ) ) ?
	mbedtls_cipher_get_block_size( &cipher_ctx ) : (unsigned int) ( filesize - offset );

	if( fread( buffer, 1, ilen, fin ) != ilen )
	{
	mbedtls_fprintf( stderr, "fread(%d bytes) failed\n",
	mbedtls_cipher_get_block_size( &cipher_ctx ) );
	goto exit;
	}

	mbedtls_md_hmac_update( &md_ctx, buffer, ilen );
	if( mbedtls_cipher_update( &cipher_ctx, buffer, ilen, output,
	&olen ) != 0 )
	{
	mbedtls_fprintf( stderr, "mbedtls_cipher_update() returned error\n" );
	goto exit;
	}

	if( fwrite( output, 1, olen, fout ) != olen )
	{
	mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
	goto exit;
	}
	}

	/*
	* Verify the message authentication code.
	*/
	mbedtls_md_hmac_finish( &md_ctx, digest );

	if( fread( buffer, 1, mbedtls_md_get_size( md_info ), fin ) != mbedtls_md_get_size( md_info ) )
	{
	mbedtls_fprintf( stderr, "fread(%d bytes) failed\n", mbedtls_md_get_size( md_info ) );
	goto exit;
	}

	/* Use constant-time buffer comparison */
	diff = 0;
	for( i = 0; i < mbedtls_md_get_size( md_info ); i++ )
	diff \|= digest[i] ^ buffer[i];

	if( diff != 0 )
	{
	mbedtls_fprintf( stderr, "HMAC check failed: wrong key, "
	"or file corrupted.\n" );
	goto exit;
	}

	/*
	* Write the final block of data
	*/
	mbedtls_cipher_finish( &cipher_ctx, output, &olen );

	if( fwrite( output, 1, olen, fout ) != olen )
	{
	mbedtls_fprintf( stderr, "fwrite(%ld bytes) failed\n", (long) olen );
	goto exit;
	}
	}

	exit_code = MBEDTLS_EXIT_SUCCESS;

	exit:
	if( fin )
	fclose( fin );
	if( fout )
	fclose( fout );

	/* Zeroize all command line arguments to also cover
	the case when the user has missed or reordered some,
	in which case the key might not be in argv[6]. */
	for( i = 0; i < argc; i++ )
	mbedtls_platform_zeroize( argv[i], strlen( argv[i] ) );

	mbedtls_platform_zeroize( IV, sizeof( IV ) );
	mbedtls_platform_zeroize( key, sizeof( key ) );
	mbedtls_platform_zeroize( buffer, sizeof( buffer ) );
	mbedtls_platform_zeroize( output, sizeof( output ) );
	mbedtls_platform_zeroize( digest, sizeof( digest ) );

	mbedtls_cipher_free( &cipher_ctx );
	mbedtls_md_free( &md_ctx );

	return( exit_code );
	}
	#endif /* MBEDTLS_CIPHER_C && MBEDTLS_MD_C && MBEDTLS_FS_IO */