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public abstract Subtract ( |
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| return | ||
internal static ECPoint ImplShamirsTrickJsf(ECPoint P, BigInteger k, ECPoint Q, BigInteger l)
{
ECCurve curve = P.Curve;
ECPoint infinity = curve.Infinity;
ECPoint eCPoint = P.Add(Q);
ECPoint eCPoint2 = P.Subtract(Q);
ECPoint[] array = new ECPoint[]
{
Q,
eCPoint2,
P,
eCPoint
};
curve.NormalizeAll(array);
ECPoint[] array2 = new ECPoint[]
{
array[3].Negate(),
array[2].Negate(),
array[1].Negate(),
array[0].Negate(),
infinity,
array[0],
array[1],
array[2],
array[3]
};
byte[] array3 = WNafUtilities.GenerateJsf(k, l);
ECPoint eCPoint3 = infinity;
int num = array3.Length;
while (--num >= 0)
{
int num2 = (int)array3[num];
int num3 = num2 << 24 >> 28;
int num4 = num2 << 28 >> 28;
int num5 = 4 + num3 * 3 + num4;
eCPoint3 = eCPoint3.TwicePlus(array2[num5]);
}
return(eCPoint3);
}
// D.3.2 pg 101
public override ECPoint Multiply(
BigInteger b)
{
if (this.IsInfinity)
{
return(this);
}
if (b.SignValue == 0)
{
return(this.curve.Infinity);
}
// BigInteger e = k.mod(n); // n == order this
BigInteger e = b;
BigInteger h = e.Multiply(BigInteger.ValueOf(3));
ECPoint R = this;
for (int i = h.BitLength - 2; i > 0; i--)
{
R = R.Twice();
if (h.TestBit(i) && !e.TestBit(i))
{
//System.out.print("+");
R = R.Add(this);
}
else if (!h.TestBit(i) && e.TestBit(i))
{
//System.out.print("-");
R = R.Subtract(this);
}
// else
// System.out.print(".");
}
// System.out.println();
return(R);
}
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);
ECPoint[] points = new ECPoint[] { Q, PsubQ, P, PaddQ };
curve.NormalizeAll(points);
ECPoint[] 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);
}
internal static ECPoint ImplShamirsTrickJsf(ECPoint P, BigInteger k, ECPoint Q, BigInteger l)
{
ECCurve curve = P.Curve;
ECPoint infinity = curve.Infinity;
ECPoint point2 = P.Add(Q);
ECPoint point3 = P.Subtract(Q);
ECPoint[] points = new ECPoint[] { Q, point3, P, point2 };
curve.NormalizeAll(points);
ECPoint[] pointArray2 = new ECPoint[] { points[3].Negate(), points[2].Negate(), points[1].Negate(), points[0].Negate(), infinity, points[0], points[1], points[2], points[3] };
byte[] buffer = WNafUtilities.GenerateJsf(k, l);
ECPoint point4 = infinity;
int length = buffer.Length;
while (--length >= 0)
{
int num2 = buffer[length];
int num3 = (num2 << 0x18) >> 0x1c;
int num4 = (num2 << 0x1c) >> 0x1c;
int index = (4 + (num3 * 3)) + num4;
point4 = point4.TwicePlus(pointArray2[index]);
}
return(point4);
}
/**
* Tests <code>ECPoint.add()</code> and <code>ECPoint.subtract()</code>
* for the given point and the given point at infinity.
*
* @param p
* The point on which the tests are performed.
* @param infinity
* The point at infinity on the same curve as <code>p</code>.
*/
private void ImplTestAddSubtract(ECPoint p, ECPoint infinity)
{
AssertPointsEqual("Twice and Add inconsistent", p.Twice(), p.Add(p));
AssertPointsEqual("Twice p - p is not p", p, p.Twice().Subtract(p));
AssertPointsEqual("TwicePlus(p, -p) is not p", p, p.TwicePlus(p.Negate()));
AssertPointsEqual("p - p is not infinity", infinity, p.Subtract(p));
AssertPointsEqual("p plus infinity is not p", p, p.Add(infinity));
AssertPointsEqual("infinity plus p is not p", p, infinity.Add(p));
AssertPointsEqual("infinity plus infinity is not infinity ", infinity, infinity.Add(infinity));
AssertPointsEqual("Twice infinity is not infinity ", infinity, infinity.Twice());
}
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);
ECPoint[] points = new ECPoint[] { Q, PsubQ, P, PaddQ };
curve.NormalizeAll(points);
ECPoint[] 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;
}
/**
* Tests <code>ECPoint.add()</code> and <code>ECPoint.subtract()</code>
* for the given point and the given point at infinity.
*
* @param p
* The point on which the tests are performed.
* @param infinity
* The point at infinity on the same curve as <code>p</code>.
*/
private void implTestAddSubtract(ECPoint p, ECPoint infinity)
{
Assert.AreEqual(p.Twice(), p.Add(p), "Twice and Add inconsistent");
Assert.AreEqual(p, p.Twice().Subtract(p), "Twice p - p is not p");
Assert.AreEqual(infinity, p.Subtract(p), "p - p is not infinity");
Assert.AreEqual(p, p.Add(infinity), "p plus infinity is not p");
Assert.AreEqual(p, infinity.Add(p), "infinity plus p is not p");
Assert.AreEqual(infinity, infinity.Add(infinity), "infinity plus infinity is not infinity ");
}