com.distrimind.bouncycastle.math.ec.tools.F2mSqrtOptimizer Maven / Gradle / Ivy
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package com.distrimind.bouncycastle.math.ec.tools;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;
import com.distrimind.bouncycastle.asn1.x9.ECNamedCurveTable;
import com.distrimind.bouncycastle.asn1.x9.X9ECParametersHolder;
import com.distrimind.bouncycastle.crypto.ec.CustomNamedCurves;
import com.distrimind.bouncycastle.math.ec.ECAlgorithms;
import com.distrimind.bouncycastle.math.ec.ECCurve;
import com.distrimind.bouncycastle.math.ec.ECFieldElement;
import com.distrimind.bouncycastle.util.Strings;
public class F2mSqrtOptimizer
{
public static void main(String[] args)
{
SortedSet names = new TreeSet(enumToList(ECNamedCurveTable.getNames()));
names.addAll(enumToList(CustomNamedCurves.getNames()));
Iterator it = names.iterator();
while (it.hasNext())
{
String name = (String)it.next();
X9ECParametersHolder x9 = CustomNamedCurves.getByNameLazy(name);
if (x9 == null)
{
x9 = ECNamedCurveTable.getByNameLazy(name);
}
if (x9 != null)
{
ECCurve curve = x9.getCurve();
if (ECAlgorithms.isF2mCurve(curve))
{
// -DM System.out.println
System.out.print(name + ":");
implPrintRootZ(curve);
}
}
}
}
public static void printRootZ(ECCurve curve)
{
if (!ECAlgorithms.isF2mCurve(curve))
{
throw new IllegalArgumentException("Sqrt optimization only defined over characteristic-2 fields");
}
implPrintRootZ(curve);
}
private static void implPrintRootZ(ECCurve curve)
{
ECFieldElement z = curve.fromBigInteger(BigInteger.valueOf(2));
ECFieldElement rootZ = z.sqrt();
// -DM System.out.println
System.out.println(Strings.toUpperCase(rootZ.toBigInteger().toString(16)));
if (!rootZ.square().equals(z))
{
throw new IllegalStateException("Optimized-sqrt sanity check failed");
}
}
private static List enumToList(Enumeration en)
{
List rv = new ArrayList();
while (en.hasMoreElements())
{
rv.add(en.nextElement());
}
return rv;
}
}