pack25519 function

void pack25519(Uint8List o, List<int> n)

Implementation

void pack25519(final Uint8List o, final List<int> n) {
  int i, j, b;
  final List<int> m = gf(), t = gf(n);
  car25519(t);
  car25519(t);
  car25519(t);
  for (j = 0; j < 2; ++j) {
    m[0] = t[0] - 0xffed;
    for (i = 1; i < 15; ++i) {
      m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
      m[i - 1] &= 0xffff;
    }
    m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
    b = (m[15] >> 16) & 1;
    m[14] &= 0xffff;
    sel25519(t, m, 1 - b);
  }
  for (i = 0; i < 16; ++i) {
    o[2 * i] = t[i] & 0xff;
    o[2 * i + 1] = t[i] >> 8;
  }
}