private static void EncodePoint(PointExt p, byte[] r, int rOff) { uint[] x = X448Field.Create(); uint[] y = X448Field.Create(); X448Field.Inv(p.z, y); X448Field.Mul(p.x, y, x); X448Field.Mul(p.y, y, y); X448Field.Normalize(x); X448Field.Normalize(y); X448Field.Encode(y, r, rOff); r[rOff + PointBytes - 1] = (byte)((x[0] & 1) << 7); }