public ECPoint Add(ECPoint b)
{
if (IsInfinity())
{
return(b);
}
if (b.IsInfinity())
{
return(this);
}
var u = Mod(b.y.ToInt() * z - y.ToInt() * b.z, curve.q);
var v = Mod(b.x.ToInt() * z - x.ToInt() * b.z, curve.q);
if (BigInteger.Zero.Equals(v))
{
if (BigInteger.Zero.Equals(u))
{
return(Twice());
}
return(curve.infinity);
}
var v2 = BigInteger.Pow(v, 2);
var v3 = v2 * v;
var x1v2 = x.ToInt() * v2;
var zu2 = BigInteger.Pow(u, 2) * z;
var x3 = Mod((((zu2 - (x1v2 << 1)) * b.z) - v3) * v, curve.q);
var y3 = Mod((((((x1v2 * 3) * u) - (y.ToInt() * v3)) - (zu2 * u)) * b.z) + (u * v3), curve.q);
var z3 = Mod((v3 * z) * b.z, curve.q);
return(new ECPoint(curve, curve.FromBigInteger(x3), curve.FromBigInteger(y3), z3));
}