release/src/router/libsodium/src/libsodium/crypto_stream/salsa2012/ref/stream_salsa2012.c

   1 /*
   2 version 20080913
   3 D. J. Bernstein
   4 Public domain.
   5 */
   6
   7 #include "api.h"
   8 #include "crypto_core_salsa2012.h"
   9
  10 typedef unsigned int uint32;
  11
  12 static const unsigned char sigma[16] = {
  13     'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'
  14 };
  15
  16 int crypto_stream(
  17         unsigned char *c,unsigned long long clen,
  18   const unsigned char *n,
  19   const unsigned char *k
  20 )
  21 {
  22   unsigned char in[16];
  23   unsigned char block[64];
  24   unsigned long long i;
  25   unsigned int u;
  26
  27   if (!clen) return 0;
  28
  29   for (i = 0;i < 8;++i) in[i] = n[i];
  30   for (i = 8;i < 16;++i) in[i] = 0;
  31
  32   while (clen >= 64) {
  33     crypto_core_salsa2012(c,in,k,sigma);
  34
  35     u = 1;
  36     for (i = 8;i < 16;++i) {
  37       u += (unsigned int) in[i];
  38       in[i] = u;
  39       u >>= 8;
  40     }
  41
  42     clen -= 64;
  43     c += 64;
  44   }
  45
  46   if (clen) {
  47     crypto_core_salsa2012(block,in,k,sigma);
  48     for (i = 0;i < clen;++i) c[i] = block[i];
  49   }
  50   return 0;
  51 }