Sha256: a405dd36543671a3af900f744d2a111e3ff76cc31efcaa7e5a1c4860811aa794

Contents?: true

Size: 1.28 KB

Versions: 7

Compression:

Stored size: 1.28 KB

Contents

#include "fe.h"

/*
Replace (f,g) with (g,f) if b == 1;
replace (f,g) with (f,g) if b == 0.

Preconditions: b in {0,1}.
*/

void fe_cswap(fe f,fe g,unsigned int b)
{
  int32_t f0 = f[0];
  int32_t f1 = f[1];
  int32_t f2 = f[2];
  int32_t f3 = f[3];
  int32_t f4 = f[4];
  int32_t f5 = f[5];
  int32_t f6 = f[6];
  int32_t f7 = f[7];
  int32_t f8 = f[8];
  int32_t f9 = f[9];
  int32_t g0 = g[0];
  int32_t g1 = g[1];
  int32_t g2 = g[2];
  int32_t g3 = g[3];
  int32_t g4 = g[4];
  int32_t g5 = g[5];
  int32_t g6 = g[6];
  int32_t g7 = g[7];
  int32_t g8 = g[8];
  int32_t g9 = g[9];
  int32_t x0 = f0 ^ g0;
  int32_t x1 = f1 ^ g1;
  int32_t x2 = f2 ^ g2;
  int32_t x3 = f3 ^ g3;
  int32_t x4 = f4 ^ g4;
  int32_t x5 = f5 ^ g5;
  int32_t x6 = f6 ^ g6;
  int32_t x7 = f7 ^ g7;
  int32_t x8 = f8 ^ g8;
  int32_t x9 = f9 ^ g9;
  b = -b;
  x0 &= b;
  x1 &= b;
  x2 &= b;
  x3 &= b;
  x4 &= b;
  x5 &= b;
  x6 &= b;
  x7 &= b;
  x8 &= b;
  x9 &= b;
  f[0] = f0 ^ x0;
  f[1] = f1 ^ x1;
  f[2] = f2 ^ x2;
  f[3] = f3 ^ x3;
  f[4] = f4 ^ x4;
  f[5] = f5 ^ x5;
  f[6] = f6 ^ x6;
  f[7] = f7 ^ x7;
  f[8] = f8 ^ x8;
  f[9] = f9 ^ x9;
  g[0] = g0 ^ x0;
  g[1] = g1 ^ x1;
  g[2] = g2 ^ x2;
  g[3] = g3 ^ x3;
  g[4] = g4 ^ x4;
  g[5] = g5 ^ x5;
  g[6] = g6 ^ x6;
  g[7] = g7 ^ x7;
  g[8] = g8 ^ x8;
  g[9] = g9 ^ x9;
}

Version data entries

7 entries across 7 versions & 1 rubygems

Version Path
x25519-1.0.4 ext/x25519_ref10/fe_cswap.c
x25519-1.0.3 ext/x25519_ref10/fe_cswap.c
x25519-1.0.2 ext/x25519_ref10/fe_cswap.c
x25519-1.0.1 ext/x25519_ref10/fe_cswap.c
x25519-1.0.0 ext/x25519_ref10/fe_cswap.c
x25519-0.2.0 ext/x25519_ref10/fe_cswap.c
x25519-0.1.0 ext/x25519/ref10/fe_cswap.c