release/src/router/libsodium/src/libsodium/crypto_stream/salsa20/ref/stream_salsa20_ref.c

   1 /*
   2 version 20080913
   3 D. J. Bernstein
   4 Public domain.
   5 */
   6
   7 #include "api.h"
   8 #include "crypto_core_salsa20.h"
   9
  10 #ifndef HAVE_AMD64_ASM
  11
  12 typedef unsigned int uint32;
  13
  14 static const unsigned char sigma[16] = {
  15     'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'
  16 };
  17
  18 int crypto_stream(
  19         unsigned char *c,unsigned long long clen,
  20   const unsigned char *n,
  21   const unsigned char *k
  22 )
  23 {
  24   unsigned char in[16];
  25   unsigned char block[64];
  26   unsigned long long i;
  27   unsigned int u;
  28
  29   if (!clen) return 0;
  30
  31   for (i = 0;i < 8;++i) in[i] = n[i];
  32   for (i = 8;i < 16;++i) in[i] = 0;
  33
  34   while (clen >= 64) {
  35     crypto_core_salsa20(c,in,k,sigma);
  36
  37     u = 1;
  38     for (i = 8;i < 16;++i) {
  39       u += (unsigned int) in[i];
  40       in[i] = u;
  41       u >>= 8;
  42     }
  43
  44     clen -= 64;
  45     c += 64;
  46   }
  47
  48   if (clen) {
  49     crypto_core_salsa20(block,in,k,sigma);
  50     for (i = 0;i < clen;++i) c[i] = block[i];
  51   }
  52   return 0;
  53 }
  54
  55 #endif