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         data_to_words(tfe->key, TF_KEY_SIZE);
  10         if (iv) {
  11                 memcpy(tfe->iv, iv, TF_BLOCK_SIZE);
  12                 data_to_words(tfe->iv, TF_BLOCK_SIZE);
  13         }
  14         tfe->carry_bytes = 0;
  15 }
  16
  17 void tfe_init(struct tfe_stream *tfe, const void *key)
  18 {
  19         tfe_init_iv(tfe, key, NULL);
  20 }
  21
  22 void tfe_emit(void *dst, size_t szdst, struct tfe_stream *tfe)
  23 {
  24         TF_BYTE_TYPE *udst = dst;
  25         size_t sz = szdst;
  26
  27         if (!dst && szdst == 0) {
  28                 memset(tfe, 0, sizeof(struct tfe_stream));
  29                 return;
  30         }
  31
  32         if (tfe->carry_bytes > 0) {
  33                 if (tfe->carry_bytes > szdst) {
  34                         memcpy(udst, tfe->carry_block, szdst);
  35                         memmove(tfe->carry_block, tfe->carry_block+szdst, tfe->carry_bytes-szdst);
  36                         tfe->carry_bytes -= szdst;
  37                         return;
  38                 }
  39
  40                 memcpy(udst, tfe->carry_block, tfe->carry_bytes);
  41                 udst += tfe->carry_bytes;
  42                 sz -= tfe->carry_bytes;
  43                 tfe->carry_bytes = 0;
  44         }
  45
  46         if (sz >= TF_BLOCK_SIZE) {
  47                 do {
  48                         tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  49                         memcpy(udst, tfe->iv, TF_BLOCK_SIZE);
  50                         data_to_words(udst, TF_BLOCK_SIZE);
  51                         udst += TF_BLOCK_SIZE;
  52                 } while ((sz -= TF_BLOCK_SIZE) >= TF_BLOCK_SIZE);
  53         }
  54
  55         if (sz) {
  56                 tf_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
  57                 memcpy(udst, tfe->iv, sz);
  58                 data_to_words(udst, TF_BLOCK_SIZE);
  59                 udst = (TF_BYTE_TYPE *)tfe->iv;
  60                 tfe->carry_bytes = TF_BLOCK_SIZE-sz;
  61                 memcpy(tfe->carry_block, udst+sz, tfe->carry_bytes);
  62         }
  63 }