//public static BigInteger SolveDLP(AffinePoint P, AffinePoint Q)
//{
// var order = P.E.HasseTheorem();
// var babySteps = new Dictionary<AffinePoint, BigInteger>();
// var m = BigIntegerExtension.Sqrt(order) + 1;
// AffinePoint babyStep;
// for (BigInteger i = 0; i < m; i++)
// {
// babyStep = (i * P.ToProjectivePoint()).ToAffinePoint();
// babySteps.Add(babyStep, i);
// Console.WriteLine(babyStep);
// }
// AffinePoint temp;
// ProjectivePoint giantStep = (m * P.ToProjectivePoint());
// for (BigInteger j = 0; j < m; j++)
// {
// temp = (Q.ToProjectivePoint() - j * giantStep).ToAffinePoint();
// Console.WriteLine(temp);
// BigInteger i = -1;
// try
// {
// i = babySteps[temp];
// }
// catch (KeyNotFoundException e) { }
// if (i != -1)
// return BigIntegerExtension.ModPositive(i + j * m, order);
// }
// return -1;
//}
public static BigInteger SolveDLP(ProjectivePoint P, ProjectivePoint Q)
{
var order = P.E.HasseTheorem();
var babySteps = new Dictionary <AffinePoint, BigInteger>();
var m = BigIntegerExtension.Sqrt(order) + 1;
AffinePoint babyStep;
for (BigInteger i = 0; i <= m; i++)
{
babyStep = (i * P).ToAffinePoint();
babySteps.Add(babyStep, i);
//Console.WriteLine(babyStep);
}
AffinePoint temp;
ProjectivePoint giantStep = (m * P);
//Console.WriteLine();
//Console.WriteLine(giantStep.ToAffinePoint());
//Console.WriteLine();
for (BigInteger j = 0; j <= m; j++)
{
temp = (Q - j * giantStep).ToAffinePoint();
// Console.WriteLine(temp);
BigInteger i = -1;
try
{
i = babySteps[temp];
}
catch (KeyNotFoundException e) { }
if (i != -1)
{
//Console.WriteLine(temp + " dfsd");
return(BigIntegerExtension.ModPositive(i + j * m, order));
}
}
//make modification with m/2 and +-iP
return(-1);
}
