internal static ECPoint ImplShamirsTrickWNaf(ECPoint P, BigInteger k, ECPointMap pointMapQ, BigInteger l)
{
bool negK = k.SignValue < 0, negL = l.SignValue < 0;
k = k.Abs();
l = l.Abs();
int width = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(System.Math.Max(k.BitLength, l.BitLength))));
ECPoint Q = WNafUtilities.MapPointWithPrecomp(P, width, true, pointMapQ);
WNafPreCompInfo infoP = WNafUtilities.GetWNafPreCompInfo(P);
WNafPreCompInfo infoQ = WNafUtilities.GetWNafPreCompInfo(Q);
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(width, k);
byte[] wnafQ = WNafUtilities.GenerateWindowNaf(width, l);
return(ImplShamirsTrickWNaf(preCompP, preCompNegP, wnafP, preCompQ, preCompNegQ, wnafQ));
}
internal static ECPoint ImplSumOfMultiplies(ECPoint[] ps, BigInteger[] ks)
{
int count = ps.Length;
bool[] negs = new bool[count];
WNafPreCompInfo[] infos = new WNafPreCompInfo[count];
byte[][] wnafs = new byte[count][];
for (int i = 0; i < count; ++i)
{
BigInteger ki = ks[i]; negs[i] = ki.SignValue < 0; ki = ki.Abs();
int minWidth = WNafUtilities.GetWindowSize(ki.BitLength, 8);
WNafPreCompInfo info = WNafUtilities.Precompute(ps[i], minWidth, true);
int width = System.Math.Min(8, info.Width);
infos[i] = info;
wnafs[i] = WNafUtilities.GenerateWindowNaf(width, ki);
}
return(ImplSumOfMultiplies(negs, infos, wnafs));
}
public static ECPoint ImplShamirsTrickWNaf(ECPoint P, BigInteger k,
ECPoint Q, BigInteger l)
{
bool negK = k.SignValue < 0, negL = l.SignValue < 0;
k = k.Abs();
l = l.Abs();
int widthP = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(k.BitLength)));
int widthQ = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(l.BitLength)));
WNafPreCompInfo infoP = WNafUtilities.Precompute(P, widthP, true);
WNafPreCompInfo infoQ = WNafUtilities.Precompute(Q, widthQ, true);
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));
}
/**
* Determine window width to use for a scalar multiplication of the given size.
*
* @param bits the bit-length of the scalar to multiply by
* @return the window size to use
*/
protected virtual int GetWindowSize(int bits)
{
return(WNafUtilities.GetWindowSize(bits));
}
internal static ECPoint ImplShamirsTrickWNaf(ECPoint P, BigInteger k, ECPointMap pointMapQ, BigInteger l)
{
bool flag = k.SignValue < 0;
bool flag2 = l.SignValue < 0;
k = k.Abs();
l = l.Abs();
int width = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(System.Math.Max(k.BitLength, l.BitLength))));
ECPoint p = WNafUtilities.MapPointWithPrecomp(P, width, includeNegated: true, pointMapQ);
WNafPreCompInfo wNafPreCompInfo = WNafUtilities.GetWNafPreCompInfo(P);
WNafPreCompInfo wNafPreCompInfo2 = WNafUtilities.GetWNafPreCompInfo(p);
ECPoint[] preCompP = (!flag) ? wNafPreCompInfo.PreComp : wNafPreCompInfo.PreCompNeg;
ECPoint[] preCompQ = (!flag2) ? wNafPreCompInfo2.PreComp : wNafPreCompInfo2.PreCompNeg;
ECPoint[] preCompNegP = (!flag) ? wNafPreCompInfo.PreCompNeg : wNafPreCompInfo.PreComp;
ECPoint[] preCompNegQ = (!flag2) ? wNafPreCompInfo2.PreCompNeg : wNafPreCompInfo2.PreComp;
byte[] wnafP = WNafUtilities.GenerateWindowNaf(width, k);
byte[] wnafQ = WNafUtilities.GenerateWindowNaf(width, l);
return(ImplShamirsTrickWNaf(preCompP, preCompNegP, wnafP, preCompQ, preCompNegQ, wnafQ));
}
internal static ECPoint ImplSumOfMultiplies(ECPoint[] ps, BigInteger[] ks)
{
int count = ps.Length;
int[] widths = new int[count];
WNafPreCompInfo[] infos = new WNafPreCompInfo[count];
byte[][] wnafs = new byte[count][];
int len = 0;
for (int i = 0; i < count; ++i)
{
widths[i] = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(ks[i].BitLength)));
infos[i] = WNafUtilities.Precompute(ps[i], widths[i], true);
wnafs[i] = WNafUtilities.GenerateWindowNaf(widths[i], ks[i]);
len = System.Math.Max(len, wnafs[i].Length);
}
ECCurve curve = ps[0].Curve;
ECPoint infinity = curve.Infinity;
ECPoint R = infinity;
int zeroes = 0;
for (int i = len - 1; i >= 0; --i)
{
ECPoint r = infinity;
for (int j = 0; j < count; ++j)
{
byte[] wnaf = wnafs[j];
int wi = i < wnaf.Length ? (int)(sbyte)wnaf[i] : 0;
if (wi != 0)
{
int n = System.Math.Abs(wi);
WNafPreCompInfo info = infos[j];
ECPoint[] table = wi < 0 ? info.PreCompNeg : info.PreComp;
r = r.Add(table[n >> 1]);
}
}
if (r == infinity)
{
++zeroes;
continue;
}
if (zeroes > 0)
{
R = R.TimesPow2(zeroes);
zeroes = 0;
}
R = R.TwicePlus(r);
}
if (zeroes > 0)
{
R = R.TimesPow2(zeroes);
}
return(R);
}
internal static ECPoint ImplShamirsTrickWNaf(ECPoint P, BigInteger k, ECPoint Q, BigInteger l)
{
int widthP = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(k.BitLength)));
int widthQ = System.Math.Max(2, System.Math.Min(16, WNafUtilities.GetWindowSize(l.BitLength)));
WNafPreCompInfo infoP = WNafUtilities.Precompute(P, widthP, true);
WNafPreCompInfo infoQ = WNafUtilities.Precompute(Q, widthQ, true);
ECPoint[] preCompP = infoP.PreComp;
ECPoint[] preCompQ = infoQ.PreComp;
ECPoint[] preCompNegP = infoP.PreCompNeg;
ECPoint[] preCompNegQ = infoQ.PreCompNeg;
byte[] wnafP = WNafUtilities.GenerateWindowNaf(widthP, k);
byte[] wnafQ = WNafUtilities.GenerateWindowNaf(widthQ, l);
int len = System.Math.Max(wnafP.Length, wnafQ.Length);
ECCurve curve = P.Curve;
ECPoint infinity = curve.Infinity;
ECPoint R = infinity;
int zeroes = 0;
for (int i = len - 1; i >= 0; --i)
{
int wiP = i < wnafP.Length ? (int)(sbyte)wnafP[i] : 0;
int wiQ = i < wnafQ.Length ? (int)(sbyte)wnafQ[i] : 0;
if ((wiP | wiQ) == 0)
{
++zeroes;
continue;
}
ECPoint r = infinity;
if (wiP != 0)
{
int nP = System.Math.Abs(wiP);
ECPoint[] tableP = wiP < 0 ? preCompNegP : preCompP;
r = r.Add(tableP[nP >> 1]);
}
if (wiQ != 0)
{
int nQ = System.Math.Abs(wiQ);
ECPoint[] tableQ = wiQ < 0 ? preCompNegQ : preCompQ;
r = r.Add(tableQ[nQ >> 1]);
}
if (zeroes > 0)
{
R = R.TimesPow2(zeroes);
zeroes = 0;
}
R = R.TwicePlus(r);
}
if (zeroes > 0)
{
R = R.TimesPow2(zeroes);
}
return(R);
}
