public static ECPoint SumOfTwoMultiplies(ECPoint P, BigInteger a, ECPoint Q, BigInteger b)
{
ECCurve cp = P.Curve;
Q = ImportPoint(cp, Q);
// Point multiplication for Koblitz curves (using WTNAF) beats Shamir's trick
{
var f2mCurve = cp as AbstractF2mCurve;
if (f2mCurve != null && f2mCurve.IsKoblitz)
{
return(ValidatePoint(P.Multiply(a).Add(Q.Multiply(b))));
}
}
var glvEndomorphism = cp.GetEndomorphism() as GlvEndomorphism;
if (glvEndomorphism != null)
{
return(ValidatePoint(
ImplSumOfMultipliesGlv(new ECPoint[] { P, Q }, new BigInteger[] { a, b }, glvEndomorphism)));
}
return(ValidatePoint(ImplShamirsTrickWNaf(P, a, Q, b)));
}
public static ECPoint SumOfMultiplies(ECPoint[] ps, BigInteger[] ks)
{
if (ps == null || ks == null || ps.Length != ks.Length || ps.Length < 1)
{
throw new ArgumentException("point and scalar arrays should be non-null, and of equal, non-zero, length");
}
int count = ps.Length;
switch (count)
{
case 1:
return(ps[0].Multiply(ks[0]));
case 2:
return(SumOfTwoMultiplies(ps[0], ks[0], ps[1], ks[1]));
default:
break;
}
ECPoint p = ps[0];
ECCurve c = p.Curve;
var imported = new ECPoint[count];
imported[0] = p;
for (int i = 1; i < count; ++i)
{
imported[i] = ImportPoint(c, ps[i]);
}
var glvEndomorphism = c.GetEndomorphism() as GlvEndomorphism;
if (glvEndomorphism != null)
{
return(ValidatePoint(ImplSumOfMultipliesGlv(imported, ks, glvEndomorphism)));
}
return(ValidatePoint(ImplSumOfMultiplies(imported, ks)));
}
