private static ECPoint SumOfTwoMultiplies(ECPoint P, BigInteger k, ECPoint Q, BigInteger l)
{
int m = Math.Max(k.GetBitLength(), l.GetBitLength());
ECPoint Z = P + Q;
ECPoint R = P.Curve.Infinity;
for (int i = m - 1; i >= 0; --i)
{
R = R.Twice();
if (k.TestBit(i))
{
if (l.TestBit(i))
R = R + Z;
else
R = R + P;
}
else
{
if (l.TestBit(i))
R = R + Q;
}
}
return R;
}