internal static ECPoint ImplSumOfMultipliesGlv(ECPoint[] ps, BigInteger[] ks, GlvEndomorphism glvEndomorphism)
{
BigInteger n = ps[0].Curve.Order;
int len = ps.Length;
BigInteger[] abs = new BigInteger[len << 1];
for (int i = 0, j = 0; i < len; ++i)
{
BigInteger[] ab = glvEndomorphism.DecomposeScalar(ks[i].Mod(n));
abs[j++] = ab[0];
abs[j++] = ab[1];
}
if (glvEndomorphism.HasEfficientPointMap)
{
return(ImplSumOfMultiplies(glvEndomorphism, ps, abs));
}
ECPoint[] pqs = new ECPoint[len << 1];
for (int i = 0, j = 0; i < len; ++i)
{
ECPoint p = ps[i];
ECPoint q = EndoUtilities.MapPoint(glvEndomorphism, p);
pqs[j++] = p;
pqs[j++] = q;
}
return(ImplSumOfMultiplies(pqs, abs));
}
internal static ECPoint ImplSumOfMultiplies(ECEndomorphism endomorphism, ECPoint[] ps, BigInteger[] ks)
{
int halfCount = ps.Length, fullCount = halfCount << 1;
bool[] negs = new bool[fullCount];
WNafPreCompInfo[] infos = new WNafPreCompInfo[fullCount];
byte[][] wnafs = new byte[fullCount][];
ECPointMap pointMap = endomorphism.PointMap;
for (int i = 0; i < halfCount; ++i)
{
int j0 = i << 1, j1 = j0 + 1;
BigInteger kj0 = ks[j0]; negs[j0] = kj0.SignValue < 0; kj0 = kj0.Abs();
BigInteger kj1 = ks[j1]; negs[j1] = kj1.SignValue < 0; kj1 = kj1.Abs();
int minWidth = WNafUtilities.GetWindowSize(System.Math.Max(kj0.BitLength, kj1.BitLength), 8);
ECPoint P = ps[i];
WNafPreCompInfo infoP = WNafUtilities.Precompute(P, minWidth, true);
ECPoint Q = EndoUtilities.MapPoint(endomorphism, P);
WNafPreCompInfo infoQ = WNafUtilities.PrecomputeWithPointMap(Q, pointMap, infoP, true);
int widthP = System.Math.Min(8, infoP.Width);
int widthQ = System.Math.Min(8, infoQ.Width);
infos[j0] = infoP;
infos[j1] = infoQ;
wnafs[j0] = WNafUtilities.GenerateWindowNaf(widthP, kj0);
wnafs[j1] = WNafUtilities.GenerateWindowNaf(widthQ, kj1);
}
return(ImplSumOfMultiplies(negs, infos, wnafs));
}
internal static ECPoint ImplShamirsTrickWNaf(ECEndomorphism endomorphism, ECPoint P, BigInteger k, BigInteger l)
{
bool negK = k.SignValue < 0, negL = l.SignValue < 0;
k = k.Abs();
l = l.Abs();
int minWidth = WNafUtilities.GetWindowSize(System.Math.Max(k.BitLength, l.BitLength), 8);
WNafPreCompInfo infoP = WNafUtilities.Precompute(P, minWidth, true);
ECPoint Q = EndoUtilities.MapPoint(endomorphism, P);
WNafPreCompInfo infoQ = WNafUtilities.PrecomputeWithPointMap(Q, endomorphism.PointMap, infoP, true);
int widthP = System.Math.Min(8, infoP.Width);
int widthQ = System.Math.Min(8, infoQ.Width);
ECPoint[] preCompP = negK ? infoP.PreCompNeg : infoP.PreComp;
ECPoint[] preCompQ = negL ? infoQ.PreCompNeg : infoQ.PreComp;
ECPoint[] preCompNegP = negK ? infoP.PreComp : infoP.PreCompNeg;
ECPoint[] preCompNegQ = negL ? infoQ.PreComp : infoQ.PreCompNeg;
byte[] wnafP = WNafUtilities.GenerateWindowNaf(widthP, k);
byte[] wnafQ = WNafUtilities.GenerateWindowNaf(widthQ, l);
return(ImplShamirsTrickWNaf(preCompP, preCompNegP, wnafP, preCompQ, preCompNegQ, wnafQ));
}
protected override ECPoint MultiplyPositive(ECPoint p, BigInteger k)
{
if (!curve.Equals(p.Curve))
{
throw new InvalidOperationException();
}
BigInteger n = p.Curve.Order;
BigInteger[] ab = glvEndomorphism.DecomposeScalar(k.Mod(n));
BigInteger a = ab[0], b = ab[1];
if (glvEndomorphism.HasEfficientPointMap)
{
return(ECAlgorithms.ImplShamirsTrickWNaf(glvEndomorphism, p, a, b));
}
ECPoint q = EndoUtilities.MapPoint(glvEndomorphism, p);
return(ECAlgorithms.ImplShamirsTrickWNaf(p, a, q, b));
}
