/**
* Multiplies a {@link NBitcoin.BouncyCastle.math.ec.AbstractF2mPoint AbstractF2mPoint}
* by an element <code>λ</code> of <code><b>Z</b>[τ]</code>
* using the window <code>τ</code>-adic NAF (TNAF) method, given the
* WTNAF of <code>λ</code>.
* @param p The AbstractF2mPoint to multiply.
* @param u The the WTNAF of <code>λ</code>..
* @return <code>λ * p</code>
*/
private static AbstractF2mPoint MultiplyFromWTnaf(AbstractF2mPoint p, sbyte[] u, PreCompInfo preCompInfo)
{
AbstractF2mCurve curve = (AbstractF2mCurve)p.Curve;
sbyte a = (sbyte)curve.A.ToBigInteger().IntValue;
AbstractF2mPoint[] pu;
if ((preCompInfo == null) || !(preCompInfo is WTauNafPreCompInfo))
{
pu = Tnaf.GetPreComp(p, a);
WTauNafPreCompInfo pre = new WTauNafPreCompInfo();
pre.PreComp = pu;
curve.SetPreCompInfo(p, PRECOMP_NAME, pre);
}
else
{
pu = ((WTauNafPreCompInfo)preCompInfo).PreComp;
}
// TODO Include negations in precomp (optionally) and use from here
AbstractF2mPoint[] puNeg = new AbstractF2mPoint[pu.Length];
for (int i = 0; i < pu.Length; ++i)
{
puNeg[i] = (AbstractF2mPoint)pu[i].Negate();
}
// q = infinity
AbstractF2mPoint q = (AbstractF2mPoint)p.Curve.Infinity;
int tauCount = 0;
for (int i = u.Length - 1; i >= 0; i--)
{
++tauCount;
int ui = u[i];
if (ui != 0)
{
q = q.TauPow(tauCount);
tauCount = 0;
ECPoint x = ui > 0 ? pu[ui >> 1] : puNeg[(-ui) >> 1];
q = (AbstractF2mPoint)q.Add(x);
}
}
if (tauCount > 0)
{
q = q.TauPow(tauCount);
}
return(q);
}
private static AbstractF2mPoint MultiplyFromWTnaf(AbstractF2mPoint p, sbyte[] u, PreCompInfo preCompInfo)
{
AbstractF2mPoint[] preComp;
AbstractF2mCurve curve = (AbstractF2mCurve)p.Curve;
sbyte intValue = (sbyte)curve.A.ToBigInteger().IntValue;
if ((preCompInfo == null) || !(preCompInfo is WTauNafPreCompInfo))
{
preComp = Tnaf.GetPreComp(p, intValue);
WTauNafPreCompInfo info = new WTauNafPreCompInfo {
PreComp = preComp
};
curve.SetPreCompInfo(p, PRECOMP_NAME, info);
}
else
{
preComp = ((WTauNafPreCompInfo)preCompInfo).PreComp;
}
AbstractF2mPoint[] pointArray2 = new AbstractF2mPoint[preComp.Length];
for (int i = 0; i < preComp.Length; i++)
{
pointArray2[i] = (AbstractF2mPoint)preComp[i].Negate();
}
AbstractF2mPoint infinity = (AbstractF2mPoint)p.Curve.Infinity;
int pow = 0;
for (int j = u.Length - 1; j >= 0; j--)
{
pow++;
int num5 = u[j];
if (num5 != 0)
{
infinity = infinity.TauPow(pow);
pow = 0;
ECPoint b = (num5 <= 0) ? pointArray2[-num5 >> 1] : preComp[num5 >> 1];
infinity = (AbstractF2mPoint)infinity.Add(b);
}
}
if (pow > 0)
{
infinity = infinity.TauPow(pow);
}
return(infinity);
}
private static AbstractF2mPoint MultiplyFromWTnaf(AbstractF2mPoint p, sbyte[] u, PreCompInfo preCompInfo)
{
AbstractF2mCurve abstractF2mCurve = (AbstractF2mCurve)p.Curve;
sbyte a = (sbyte)abstractF2mCurve.A.ToBigInteger().IntValue;
AbstractF2mPoint[] preComp;
if (preCompInfo == null || !(preCompInfo is WTauNafPreCompInfo))
{
preComp = Tnaf.GetPreComp(p, a);
WTauNafPreCompInfo wTauNafPreCompInfo = new WTauNafPreCompInfo();
wTauNafPreCompInfo.PreComp = preComp;
abstractF2mCurve.SetPreCompInfo(p, PRECOMP_NAME, wTauNafPreCompInfo);
}
else
{
preComp = ((WTauNafPreCompInfo)preCompInfo).PreComp;
}
AbstractF2mPoint[] array = new AbstractF2mPoint[preComp.Length];
for (int i = 0; i < preComp.Length; i++)
{
array[i] = (AbstractF2mPoint)preComp[i].Negate();
}
AbstractF2mPoint abstractF2mPoint = (AbstractF2mPoint)p.Curve.Infinity;
int num = 0;
for (int num2 = u.Length - 1; num2 >= 0; num2--)
{
num++;
int num3 = u[num2];
if (num3 != 0)
{
abstractF2mPoint = abstractF2mPoint.TauPow(num);
num = 0;
ECPoint b = ((num3 > 0) ? preComp[num3 >> 1] : array[-num3 >> 1]);
abstractF2mPoint = (AbstractF2mPoint)abstractF2mPoint.Add(b);
}
}
if (num > 0)
{
abstractF2mPoint = abstractF2mPoint.TauPow(num);
}
return(abstractF2mPoint);
}