libhmac/hmac.h

   1 #ifndef hmac_h
   2 #define hmac_h
   3
   4 #include        <string.h>
   5
   6 /*
   7 ** Copyright 1998 - 2005 Double Precision, Inc.
   8 ** See COPYING for distribution information.
   9 */
  10
  11 #ifdef  __cplusplus
  12 extern "C" {
  13 #endif
  14
  15 static const char hmac_h_rcsid[]="$Id: hmac.h,v 1.7 2009/06/27 17:12:00 mrsam Exp $";
  16
  17 struct hmac_hashinfo {  /* HMAC hash function descriptor */
  18
  19         const char *hh_name;    /* Name of this hash function (md5, sha1...) */
  20
  21         size_t hh_B;    /* Length of compression blocks */
  22         size_t hh_L;    /* Length of hash outputs */
  23
  24         size_t hh_S;    /* Length of 'context structure' */
  25
  26         /* Hash functions */
  27
  28         void (*hh_init)(void *);        /* Initialize context structure */
  29         void (*hh_hash)(void *, const void *, unsigned);
  30                                         /* Feed the hash function */
  31         void (*hh_endhash)(void *, unsigned long); /* Calculate final hash */
  32
  33         void (*hh_getdigest)(void *, unsigned char *); /* Get the hash value */
  34         void (*hh_setdigest)(void *, const unsigned char *);
  35                                                 /* Set the hash value */
  36
  37         /* Some helper functions */
  38
  39         /* Allocate context on stack, instead of mallocing it.  Calls the
  40         ** provided function pointer, with context as first arg.  The second
  41         ** arg will be passed as provided.
  42         */
  43
  44         void (*hh_allocacontext)(void (*)(void *, void *), void *);
  45
  46         /* Like allocacontext, but alloc buffer for hash value, hh_L */
  47
  48         void (*hh_allocaval)(void (*)(unsigned char *, void *), void *);
  49
  50         } ;
  51
  52 /* Known hash functions */
  53
  54 extern struct hmac_hashinfo hmac_md5, hmac_sha1, hmac_sha256;
  55
  56 /*
  57 ** List of installed hash functions, dynamically generated at configuration
  58 ** time.
  59 */
  60
  61 extern struct hmac_hashinfo *hmac_list[];
  62
  63 /*
  64    To calculate an HMAC, allocate three buffers - outer, inner, and hash.
  65    Call hmac_hashkey, then hmac_hashtext.
  66
  67    After hmac_haskey returns, the contents of inner and outer can be
  68    saved, as they contain a complete intermediate state of the hash
  69    calculation.
  70 */
  71
  72 void hmac_hashkey(
  73         const struct hmac_hashinfo *,
  74         const char *,   /* Key */
  75         size_t, /* Key length */
  76         unsigned char *,        /* Output - outer buffer, prehashed */
  77         unsigned char *);       /* Output - inner buffer, prehashed */
  78
  79 void hmac_hashtext (
  80         const struct hmac_hashinfo *,
  81         const char *,   /* Text */
  82         size_t, /* Text length */
  83         const unsigned char *,  /* outer buffer, prehashed */
  84         const unsigned char *,  /* inner buffer, prehashed */
  85         unsigned char *);       /* Output - the hash */
  86
  87 #ifdef  __cplusplus
  88 }
  89 #endif
  90
  91 #endif