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      1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
      2  *
      3  * LibTomCrypt is a library that provides various cryptographic
      4  * algorithms in a highly modular and flexible manner.
      5  *
      6  * The library is free for all purposes without any express
      7  * guarantee it works.
      8  *
      9  * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com
     10  */
     11 #include "tomcrypt.h"
     12 
     13 /**
     14   @file xcbc_file.c
     15   XCBC support, process a file, Tom St Denis
     16 */
     17 
     18 #ifdef LTC_XCBC
     19 
     20 /**
     21    XCBC a file
     22    @param cipher   The index of the cipher desired
     23    @param key      The secret key
     24    @param keylen   The length of the secret key (octets)
     25    @param filename The name of the file you wish to XCBC
     26    @param out      [out] Where the authentication tag is to be stored
     27    @param outlen   [in/out] The max size and resulting size of the authentication tag
     28    @return CRYPT_OK if successful, CRYPT_NOP if file support has been disabled
     29 */
     30 int xcbc_file(int cipher,
     31               const unsigned char *key, unsigned long keylen,
     32               const char *filename,
     33                     unsigned char *out, unsigned long *outlen)
     34 {
     35 #ifdef LTC_NO_FILE
     36    return CRYPT_NOP;
     37 #else
     38    int err, x;
     39    xcbc_state xcbc;
     40    FILE *in;
     41    unsigned char buf[512];
     42 
     43    LTC_ARGCHK(key      != NULL);
     44    LTC_ARGCHK(filename != NULL);
     45    LTC_ARGCHK(out      != NULL);
     46    LTC_ARGCHK(outlen   != NULL);
     47 
     48    in = fopen(filename, "rb");
     49    if (in == NULL) {
     50       return CRYPT_FILE_NOTFOUND;
     51    }
     52 
     53    if ((err = xcbc_init(&xcbc, cipher, key, keylen)) != CRYPT_OK) {
     54       fclose(in);
     55       return err;
     56    }
     57 
     58    do {
     59       x = fread(buf, 1, sizeof(buf), in);
     60       if ((err = xcbc_process(&xcbc, buf, x)) != CRYPT_OK) {
     61          fclose(in);
     62          return err;
     63       }
     64    } while (x == sizeof(buf));
     65    fclose(in);
     66 
     67    if ((err = xcbc_done(&xcbc, out, outlen)) != CRYPT_OK) {
     68       return err;
     69    }
     70 
     71 #ifdef LTC_CLEAN_STACK
     72    zeromem(buf, sizeof(buf));
     73 #endif
     74 
     75    return CRYPT_OK;
     76 #endif
     77 }
     78 
     79 #endif
     80 
     81 /* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_file.c,v $ */
     82 /* $Revision: 1.1 $ */
     83 /* $Date: 2006/11/03 01:56:41 $ */
     84