public static EllipticCurvePoint Double(EllipticCurvePoint point)
{
var result = new EllipticCurvePoint(point.curve);
var P = point.P;
var A = point.curve.A;
var lambda = (3 * point.X * point.X + A) * ((2 * point.Y).ModInverse(P)) % P;
result.X = (lambda * lambda - 2 * point.X) % P;
result.Y = (lambda * (point.X - result.X) - point.Y) % P;
result.X += result.X < 0 ? P : 0;
result.Y += result.Y < 0 ? P : 0;
return(result);
}
public static EllipticCurvePoint operator *(EllipticCurvePoint point, int d)
{
if (d < 0)
{
Console.WriteLine("Error: In multiply on N, N is less 0");
return(point);
}
var binaryString = Convert.ToString(d, 2);
var result = new EllipticCurvePoint(point);
for (var i = 1; i < binaryString.Length; i++)
{
result = Double(result);
if (binaryString[i] == '1')
{
result = result + point;
}
}
return(result);
}
public EllipticCurvePoint Multiply(BigInteger N)
{
var curvePoint = this;
if (N < 0)
{
Console.WriteLine("Error: In multiply on N, N is less 0");
return(curvePoint);
}
var binaryString = N.ToBinaryString();
var result = new EllipticCurvePoint(curvePoint);
for (var i = 1; i < binaryString.Length; i++)
{
result = Double(result);
if (binaryString[i] == '1')
{
result = result + curvePoint;
}
}
return(result);
}
public EllipticCurvePoint(EllipticCurvePoint point)
{
curve = point.curve;
this.point = point.point;
}
