xcbc_file.c revision f7fc46c63fdc8f39234fea409b8dbe116d73ebf8 
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@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*/
30int 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