tfe.c

   1 #include <string.h>
   2 #include "tfdef.h"
   3 #include "tfe.h"
   4
   5 void tfe_init_iv(struct tfe_stream *tfe, const void *key, const void *iv)
   6 {
   7         memset(tfe, 0, sizeof(struct tfe_stream));
   8         memcpy(tfe->key, key, TF_KEY_SIZE);
   9         if (iv) memcpy(tfe->iv, iv, TF_BLOCK_SIZE);
  10         tfe->tidx = 0;
  11 }
  12
  13 void tfe_init(struct tfe_stream *tfe, const void *key)
  14 {
  15         tfe_init_iv(tfe, key, NULL);
  16 }
  17
  18 void tfe_emit(void *dst, size_t szdst, struct tfe_stream *tfe)
  19 {
  20         TF_BYTE_TYPE *udst = dst;
  21         size_t sz = szdst, trem;
  22
  23         if (!dst && szdst == 0) {
  24                 memset(tfe, 0, sizeof(struct tfe_stream));
  25                 return;
  26         }
  27
  28         if (tfe->tidx > 0) {
  29                 trem = TF_BLOCK_SIZE-tfe->tidx;
  30
  31                 if (szdst <= trem) {
  32                         memcpy(udst, &tfe->tmp[tfe->tidx], szdst);
  33                         tfe->tidx += szdst;
  34                         if (tfe->tidx >= TF_BLOCK_SIZE) tfe->tidx = 0;
  35                         return;
  36                 }
  37
  38                 memcpy(udst, &tfe->tmp[tfe->tidx], trem);
  39                 udst += trem;
  40                 sz -= trem;
  41                 tfe->tidx = 0;
  42         }
  43
  44         if (sz >= TF_BLOCK_SIZE) {
  45                 do {
  46                         tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  47                         memcpy(udst, tfe->iv, TF_BLOCK_SIZE);
  48                         data_to_words(udst, TF_BLOCK_SIZE);
  49                         udst += TF_BLOCK_SIZE;
  50                 } while ((sz -= TF_BLOCK_SIZE) >= TF_BLOCK_SIZE);
  51         }
  52
  53         if (sz) {
  54                 tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  55                 memcpy(tfe->tmp, tfe->iv, TF_BLOCK_SIZE);
  56                 data_to_words(tfe->tmp, TF_BLOCK_SIZE);
  57                 memcpy(udst, tfe->tmp, sz);
  58                 tfe->tidx = sz;
  59         }
  60 }