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