libhmac/hmac.c

   1 /*
   2 ** Copyright 1998 - 1999 Double Precision, Inc.
   3 ** See COPYING for distribution information.
   4 */
   5
   6 #if     HAVE_CONFIG_H
   7 #include        "config.h"
   8 #endif
   9
  10 #include        "hmac.h"
  11
  12 static const char rcsid[]="$Id: hmac.c,v 1.4 2006/01/22 03:37:04 mrsam Exp $";
  13
  14 struct hmac_hashinfo *hmac_list[]= {HMAC_LIST};
  15
  16 struct hhki {
  17         const struct hmac_hashinfo *hh;
  18         const char *k;
  19         size_t kl;
  20         unsigned char *kxopad;
  21         unsigned char *kxipad;
  22
  23         void *context;
  24         } ;
  25
  26 static void dohashkey(unsigned char *, void *);
  27 static void docalcc(void *, void *);
  28
  29 void hmac_hashkey(const struct hmac_hashinfo *hh, const char *k,
  30         size_t kl, unsigned char *kxopad, unsigned char *kxipad)
  31 {
  32 struct hhki i;
  33
  34         i.hh=hh;
  35         i.k=k;
  36         i.kl=kl;
  37         i.kxopad=kxopad;
  38         i.kxipad=kxipad;
  39
  40         (*hh->hh_allocacontext)( docalcc, (void *)&i );
  41 }
  42
  43 static void dokeycalc(struct hhki *);
  44
  45 static void docalcc(void *c, void *v)
  46 {
  47 struct hhki *i=(struct hhki *)v;
  48
  49         i->context=c;
  50
  51         if (i->kl > i->hh->hh_B)
  52                 (*i->hh->hh_allocaval)(dohashkey, (void *)i);
  53         else
  54                 dokeycalc( i );
  55 }
  56
  57 static void dohashkey(unsigned char *keybuf, void *v)
  58 {
  59 struct hhki *i=(struct hhki *)v;
  60
  61         (*i->hh->hh_init)(i->context);
  62         (*i->hh->hh_hash)(i->context, i->k, i->kl);
  63         (*i->hh->hh_endhash)(i->context, i->kl);
  64         (*i->hh->hh_getdigest)(i->context, keybuf);
  65         i->k=(char *)keybuf;
  66         i->kl=i->hh->hh_L;
  67         dokeycalc(i);
  68 }
  69
  70 static void dokeycalc(struct hhki *i)
  71 {
  72 char    buf[64];        /* Random guess :-) */
  73 unsigned n;
  74 unsigned l;
  75
  76         (*i->hh->hh_init)(i->context);
  77         n=0;
  78         for (l=0; l<i->hh->hh_B; l++)
  79         {
  80                 buf[n] = ( l < i->kl ? i->k[l]:0) ^ 0x5C;
  81                 if ( ++n >= sizeof(buf))
  82                 {
  83                         (*i->hh->hh_hash)(i->context, buf, sizeof(buf));
  84                         n=0;
  85                 }
  86         }
  87         if (n)
  88                 (*i->hh->hh_hash)(i->context, buf, n);
  89         (*i->hh->hh_getdigest)(i->context, i->kxopad);
  90
  91         (*i->hh->hh_init)(i->context);
  92         n=0;
  93         for (l=0; l<i->hh->hh_B; l++)
  94         {
  95                 buf[n] = ( l < i->kl ? i->k[l]:0) ^ 0x36;
  96                 if ( ++n >= sizeof(buf))
  97                 {
  98                         (*i->hh->hh_hash)(i->context, buf, sizeof(buf));
  99                         n=0;
 100                 }
 101         }
 102         if (n)
 103                 (*i->hh->hh_hash)(i->context, buf, n);
 104         (*i->hh->hh_getdigest)(i->context, i->kxipad);
 105 }
 106
 107 struct hhko {
 108         const struct hmac_hashinfo *hh;
 109         const char *t;
 110         size_t tl;
 111         const unsigned char *kxopad;
 112         const unsigned char *kxipad;
 113         unsigned char *hash;
 114         } ;
 115
 116 static void docalch(void *, void *);
 117
 118 void hmac_hashtext (
 119         const struct hmac_hashinfo *hh,
 120         const char *t,
 121         size_t tl,
 122         const unsigned char *kxopad,
 123         const unsigned char *kxipad,
 124         unsigned char *hash)
 125 {
 126 struct hhko o;
 127
 128         o.hh=hh;
 129         o.t=t;
 130         o.tl=tl;
 131         o.kxopad=kxopad;
 132         o.kxipad=kxipad;
 133         o.hash=hash;
 134
 135         (*hh->hh_allocacontext)( docalch, (void *)&o );
 136 }
 137
 138 static void docalch(void *c, void *v)
 139 {
 140 struct hhko *o=(struct hhko *)v;
 141
 142         (o->hh->hh_setdigest)(c, o->kxipad);
 143         (o->hh->hh_hash)(c, o->t, o->tl);
 144         (o->hh->hh_endhash)(c, o->tl+o->hh->hh_B);
 145         (o->hh->hh_getdigest)(c, o->hash);
 146
 147         (o->hh->hh_setdigest)(c, o->kxopad);
 148         (o->hh->hh_hash)(c, o->hash, o->hh->hh_L);
 149         (o->hh->hh_endhash)(c, o->hh->hh_L + o->hh->hh_B);
 150         (o->hh->hh_getdigest)(c, o->hash);
 151 }