| public NormalizeAll ( NBitcoin.BouncyCastle.Math.EC.ECPoint points ) : void | ||
| points | NBitcoin.BouncyCastle.Math.EC.ECPoint | |
| return | void | |
internal static ECPoint ImplShamirsTrickJsf(ECPoint P, BigInteger k, ECPoint Q, BigInteger l)
{
ECCurve curve = P.Curve;
ECPoint infinity = curve.Infinity;
// TODO conjugate co-Z addition (ZADDC) can return both of these
ECPoint PaddQ = P.Add(Q);
ECPoint PsubQ = P.Subtract(Q);
var points = new ECPoint[] { Q, PsubQ, P, PaddQ };
curve.NormalizeAll(points);
var table = new ECPoint[] {
points[3].Negate(), points[2].Negate(), points[1].Negate(),
points[0].Negate(), infinity, points[0],
points[1], points[2], points[3]
};
byte[] jsf = WNafUtilities.GenerateJsf(k, l);
ECPoint R = infinity;
int i = jsf.Length;
while (--i >= 0)
{
int jsfi = jsf[i];
// NOTE: The shifting ensures the sign is extended correctly
int kDigit = ((jsfi << 24) >> 28), lDigit = ((jsfi << 28) >> 28);
int index = 4 + (kDigit * 3) + lDigit;
R = R.TwicePlus(table[index]);
}
return(R);
}
