/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com */#include "tomcrypt.h"/**  @file hmac_file.c  HMAC support, process a file, Tom St Denis/Dobes Vandermeer*/#ifdef LTC_HMAC/**  HMAC a file  @param hash     The index of the hash you wish to use  @param fname    The name of the file you wish to HMAC  @param key      The secret key  @param keylen   The length of the secret key  @param out      [out] The HMAC authentication tag  @param outlen   [in/out]  The max size and resulting size of the authentication tag  @return CRYPT_OK if successful, CRYPT_NOP if file support has been disabled*/int hmac_file(int hash, const char *fname,               const unsigned char *key, unsigned long keylen,                     unsigned char *out, unsigned long *outlen){#ifdef LTC_NO_FILE    return CRYPT_NOP;#else   hmac_state hmac;   FILE *in;   unsigned char buf[512];   size_t x;   int err;   LTC_ARGCHK(fname  != NULL);   LTC_ARGCHK(key    != NULL);   LTC_ARGCHK(out    != NULL);   LTC_ARGCHK(outlen != NULL);      if((err = hash_is_valid(hash)) != CRYPT_OK) {       return err;   }   if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {       return err;   }   in = fopen(fname, "rb");   if (in == NULL) {      return CRYPT_FILE_NOTFOUND;   }   /* process the file contents */   do {      x = fread(buf, 1, sizeof(buf), in);      if ((err = hmac_process(&hmac, buf, (unsigned long)x)) != CRYPT_OK) {         /* we don't trap this error since we're already returning an error! */         fclose(in);         return err;      }   } while (x == sizeof(buf));   if (fclose(in) != 0) {      return CRYPT_ERROR;   }   /* get final hmac */   if ((err = hmac_done(&hmac, out, outlen)) != CRYPT_OK) {      return err;   }#ifdef LTC_CLEAN_STACK   /* clear memory */   zeromem(buf, sizeof(buf));#endif      return CRYPT_OK;#endif}#endif/* $Source: /cvs/libtom/libtomcrypt/src/mac/hmac/hmac_file.c,v $ *//* $Revision: 1.5 $ *//* $Date: 2006/11/03 00:39:49 $ */