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->carry_bytes = 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;
  22
  23         if (!dst && szdst == 0) {
  24                 memset(tfe, 0, sizeof(struct tfe_stream));
  25                 return;
  26         }
  27
  28         if (tfe->carry_bytes > 0) {
  29                 if (tfe->carry_bytes > szdst) {
  30                         memcpy(udst, tfe->carry_block, szdst);
  31                         memmove(tfe->carry_block, tfe->carry_block+szdst, tfe->carry_bytes-szdst);
  32                         tfe->carry_bytes -= szdst;
  33                         return;
  34                 }
  35
  36                 memcpy(udst, tfe->carry_block, tfe->carry_bytes);
  37                 udst += tfe->carry_bytes;
  38                 sz -= tfe->carry_bytes;
  39                 tfe->carry_bytes = 0;
  40         }
  41
  42         if (sz >= TF_BLOCK_SIZE) {
  43                 do {
  44                         tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  45                         memcpy(udst, tfe->iv, TF_BLOCK_SIZE);
  46                         data_to_words(udst, TF_BLOCK_SIZE);
  47                         udst += TF_BLOCK_SIZE;
  48                 } while ((sz -= TF_BLOCK_SIZE) >= TF_BLOCK_SIZE);
  49         }
  50
  51         if (sz) {
  52                 tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  53                 memcpy(udst, tfe->iv, sz);
  54                 data_to_words(udst, TF_BLOCK_SIZE);
  55                 udst = (TF_BYTE_TYPE *)tfe->iv;
  56                 tfe->carry_bytes = TF_BLOCK_SIZE-sz;
  57                 memcpy(tfe->carry_block, udst+sz, tfe->carry_bytes);
  58         }
  59 }