release/src/router/libsodium/src/libsodium/crypto_stream/salsa20/ref/xor_salsa20_ref.c

   1 /*
   2 version 20140420
   3 D. J. Bernstein
   4 Public domain.
   5 */
   6
   7 #include <stdint.h>
   8
   9 #include "crypto_core_salsa20.h"
  10 #include "crypto_stream_salsa20.h"
  11 #include "utils.h"
  12
  13 #ifndef HAVE_AMD64_ASM
  14
  15 int crypto_stream_salsa20_xor_ic(
  16         unsigned char *c,
  17   const unsigned char *m,unsigned long long mlen,
  18   const unsigned char *n, uint64_t ic,
  19   const unsigned char *k
  20 )
  21 {
  22   unsigned char in[16];
  23   unsigned char block[64];
  24   unsigned char kcopy[32];
  25   unsigned int i;
  26   unsigned int u;
  27
  28   if (!mlen) return 0;
  29
  30   for (i = 0;i < 32;++i) kcopy[i] = k[i];
  31   for (i = 0;i < 8;++i) in[i] = n[i];
  32   for (i = 8;i < 16;++i) {
  33       in[i] = (unsigned char) (ic & 0xff);
  34       ic >>= 8;
  35   }
  36
  37   while (mlen >= 64) {
  38     crypto_core_salsa20(block,in,kcopy,NULL);
  39     for (i = 0;i < 64;++i) c[i] = m[i] ^ block[i];
  40
  41     u = 1;
  42     for (i = 8;i < 16;++i) {
  43       u += (unsigned int) in[i];
  44       in[i] = u;
  45       u >>= 8;
  46     }
  47
  48     mlen -= 64;
  49     c += 64;
  50     m += 64;
  51   }
  52
  53   if (mlen) {
  54     crypto_core_salsa20(block,in,kcopy,NULL);
  55     for (i = 0;i < (unsigned int) mlen;++i) c[i] = m[i] ^ block[i];
  56   }
  57   sodium_memzero(block, sizeof block);
  58   sodium_memzero(kcopy, sizeof kcopy);
  59
  60   return 0;
  61 }
  62
  63 #endif