/**
* Does the precomputation for WTNAF multiplication.
* @param p The <code>ECPoint</code> for which to do the precomputation.
* @param a The parameter <code>a</code> of the elliptic curve.
* @return The precomputation array for <code>p</code>.
*/
public static F2mPoint[] GetPreComp(F2mPoint p, sbyte a)
{
F2mPoint[] pu;
pu = new F2mPoint[16];
pu[1] = p;
sbyte[][] alphaTnaf;
if (a == 0)
{
alphaTnaf = Tnaf.Alpha0Tnaf;
}
else
{
// a == 1
alphaTnaf = Tnaf.Alpha1Tnaf;
}
int precompLen = alphaTnaf.Length;
for (int i = 3; i < precompLen; i = i + 2)
{
pu[i] = Tnaf.MultiplyFromTnaf(p, alphaTnaf[i]);
}
return(pu);
}
/**
* Does the precomputation for WTNAF multiplication.
* @param p The <code>ECPoint</code> for which to do the precomputation.
* @param a The parameter <code>a</code> of the elliptic curve.
* @return The precomputation array for <code>p</code>.
*/
public static AbstractF2mPoint[] GetPreComp(AbstractF2mPoint p, sbyte a)
{
sbyte[][] alphaTnaf = (a == 0) ? Tnaf.Alpha0Tnaf : Tnaf.Alpha1Tnaf;
AbstractF2mPoint[] pu = new AbstractF2mPoint[(uint)(alphaTnaf.Length + 1) >> 1];
pu[0] = p;
uint precompLen = (uint)alphaTnaf.Length;
for (uint i = 3; i < precompLen; i += 2)
{
pu[i >> 1] = Tnaf.MultiplyFromTnaf(p, alphaTnaf[i]);
}
p.Curve.NormalizeAll(pu);
return(pu);
}
