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package org.bouncycastle.jcajce.provider.asymmetric.util;
import java.math.BigInteger;
import java.security.spec.ECField;
import java.security.spec.ECFieldF2m;
import java.security.spec.ECFieldFp;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.EllipticCurve;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import org.bouncycastle.asn1.x9.ECNamedCurveTable;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.crypto.ec.CustomNamedCurves;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveSpec;
import org.bouncycastle.math.ec.ECAlgorithms;
import org.bouncycastle.math.ec.ECCurve;
public class EC5Util
{
private static Map customCurves = new HashMap();
static
{
Enumeration e = CustomNamedCurves.getNames();
while (e.hasMoreElements())
{
String name = (String)e.nextElement();
X9ECParameters curveParams = ECNamedCurveTable.getByName(name);
if (curveParams != null) // there may not be a regular curve, may just be a custom curve.
{
customCurves.put(curveParams.getCurve(), CustomNamedCurves.getByName(name).getCurve());
}
}
}
public static EllipticCurve convertCurve(
ECCurve curve,
byte[] seed)
{
// TODO: the Sun EC implementation doesn't currently handle the seed properly
// so at the moment it's set to null. Should probably look at making this configurable
if (ECAlgorithms.isFpCurve(curve))
{
return new EllipticCurve(new ECFieldFp(curve.getField().getCharacteristic()), curve.getA().toBigInteger(), curve.getB().toBigInteger(), null);
}
else
{
ECCurve.F2m curveF2m = (ECCurve.F2m)curve;
int ks[];
if (curveF2m.isTrinomial())
{
ks = new int[] { curveF2m.getK1() };
return new EllipticCurve(new ECFieldF2m(curveF2m.getM(), ks), curve.getA().toBigInteger(), curve.getB().toBigInteger(), null);
}
else
{
ks = new int[] { curveF2m.getK3(), curveF2m.getK2(), curveF2m.getK1() };
return new EllipticCurve(new ECFieldF2m(curveF2m.getM(), ks), curve.getA().toBigInteger(), curve.getB().toBigInteger(), null);
}
}
}
public static ECCurve convertCurve(
EllipticCurve ec)
{
ECField field = ec.getField();
BigInteger a = ec.getA();
BigInteger b = ec.getB();
if (field instanceof ECFieldFp)
{
ECCurve.Fp curve = new ECCurve.Fp(((ECFieldFp)field).getP(), a, b);
if (customCurves.containsKey(curve))
{
return (ECCurve)customCurves.get(curve);
}
return curve;
}
else
{
ECFieldF2m fieldF2m = (ECFieldF2m)field;
int m = fieldF2m.getM();
int ks[] = ECUtil.convertMidTerms(fieldF2m.getMidTermsOfReductionPolynomial());
return new ECCurve.F2m(m, ks[0], ks[1], ks[2], a, b);
}
}
public static ECParameterSpec convertSpec(
EllipticCurve ellipticCurve,
org.bouncycastle.jce.spec.ECParameterSpec spec)
{
if (spec instanceof ECNamedCurveParameterSpec)
{
return new ECNamedCurveSpec(
((ECNamedCurveParameterSpec)spec).getName(),
ellipticCurve,
new ECPoint(
spec.getG().getAffineXCoord().toBigInteger(),
spec.getG().getAffineYCoord().toBigInteger()),
spec.getN(),
spec.getH());
}
else
{
return new ECParameterSpec(
ellipticCurve,
new ECPoint(
spec.getG().getAffineXCoord().toBigInteger(),
spec.getG().getAffineYCoord().toBigInteger()),
spec.getN(),
spec.getH().intValue());
}
}
public static org.bouncycastle.jce.spec.ECParameterSpec convertSpec(
ECParameterSpec ecSpec,
boolean withCompression)
{
ECCurve curve = convertCurve(ecSpec.getCurve());
return new org.bouncycastle.jce.spec.ECParameterSpec(
curve,
convertPoint(curve, ecSpec.getGenerator(), withCompression),
ecSpec.getOrder(),
BigInteger.valueOf(ecSpec.getCofactor()),
ecSpec.getCurve().getSeed());
}
public static org.bouncycastle.math.ec.ECPoint convertPoint(
ECParameterSpec ecSpec,
ECPoint point,
boolean withCompression)
{
return convertPoint(convertCurve(ecSpec.getCurve()), point, withCompression);
}
public static org.bouncycastle.math.ec.ECPoint convertPoint(
ECCurve curve,
ECPoint point,
boolean withCompression)
{
return curve.createPoint(point.getAffineX(), point.getAffineY(), withCompression);
}
}
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