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package org.bouncycastle.eac.jcajce;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Provider;
import java.security.PublicKey;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECField;
import java.security.spec.ECFieldFp;
import java.security.spec.EllipticCurve;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPublicKeySpec;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.eac.EACObjectIdentifiers;
import org.bouncycastle.asn1.eac.ECDSAPublicKey;
import org.bouncycastle.asn1.eac.PublicKeyDataObject;
import org.bouncycastle.asn1.eac.RSAPublicKey;
import org.bouncycastle.eac.EACException;
import org.bouncycastle.jce.spec.ECParameterSpec;
import org.bouncycastle.jce.spec.ECPublicKeySpec;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECPoint;
public class JcaPublicKeyConverter
{
private EACHelper helper = new DefaultEACHelper();
public JcaPublicKeyConverter setProvider(String providerName)
{
this.helper = new NamedEACHelper(providerName);
return this;
}
public JcaPublicKeyConverter setProvider(Provider provider)
{
this.helper = new ProviderEACHelper(provider);
return this;
}
public PublicKey getKey(PublicKeyDataObject publicKeyDataObject)
throws EACException, InvalidKeySpecException
{
if (publicKeyDataObject.getUsage().on(EACObjectIdentifiers.id_TA_ECDSA))
{
return getECPublicKeyPublicKey((ECDSAPublicKey)publicKeyDataObject);
}
else
{
RSAPublicKey pubKey = (RSAPublicKey)publicKeyDataObject;
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(pubKey.getModulus(), pubKey.getPublicExponent());
try
{
KeyFactory factk = helper.createKeyFactory("RSA");
return factk.generatePublic(pubKeySpec);
}
catch (NoSuchProviderException e)
{
throw new EACException("cannot find provider: " + e.getMessage(), e);
}
catch (NoSuchAlgorithmException e)
{
throw new EACException("cannot find algorithm ECDSA: " + e.getMessage(), e);
}
}
}
private PublicKey getECPublicKeyPublicKey(ECDSAPublicKey key)
throws EACException, InvalidKeySpecException
{
ECParameterSpec spec = getParams(key);
ECCurve curve = spec.getCurve();
ECPoint point = curve.decodePoint(key.getPublicPointY());
ECPublicKeySpec pubKeySpec = new ECPublicKeySpec(point, spec);
KeyFactory factk;
try
{
factk = helper.createKeyFactory("ECDSA");
}
catch (NoSuchProviderException e)
{
throw new EACException("cannot find provider: " + e.getMessage(), e);
}
catch (NoSuchAlgorithmException e)
{
throw new EACException("cannot find algorithm ECDSA: " + e.getMessage(), e);
}
return factk.generatePublic(pubKeySpec);
}
private ECParameterSpec getParams(ECDSAPublicKey key)
{
if (!key.hasParameters())
{
throw new IllegalArgumentException("Public key does not contains EC Params");
}
BigInteger p = key.getPrimeModulusP();
ECCurve.Fp curve = new ECCurve.Fp(p, key.getFirstCoefA(), key.getSecondCoefB());
ECPoint G = curve.decodePoint(key.getBasePointG());
BigInteger order = key.getOrderOfBasePointR();
BigInteger coFactor = key.getCofactorF();
// TODO: update to use JDK 1.5 EC API
ECParameterSpec ecspec = new ECParameterSpec(curve, G, order, coFactor);
return ecspec;
}
public PublicKeyDataObject getPublicKeyDataObject(ASN1ObjectIdentifier usage, PublicKey publicKey)
{
if (publicKey instanceof java.security.interfaces.RSAPublicKey)
{
java.security.interfaces.RSAPublicKey pubKey = (java.security.interfaces.RSAPublicKey)publicKey;
return new RSAPublicKey(usage, pubKey.getModulus(), pubKey.getPublicExponent());
}
else
{
ECPublicKey pubKey = (ECPublicKey)publicKey;
java.security.spec.ECParameterSpec params = pubKey.getParams();
return new ECDSAPublicKey(
usage,
((ECFieldFp)params.getCurve().getField()).getP(),
params.getCurve().getA(), params.getCurve().getB(),
convertPoint(convertCurve(params.getCurve()), params.getGenerator(), false).getEncoded(),
params.getOrder(),
convertPoint(convertCurve(params.getCurve()), pubKey.getW(), false).getEncoded(),
params.getCofactor());
}
}
private static org.bouncycastle.math.ec.ECPoint convertPoint(
ECCurve curve,
java.security.spec.ECPoint point,
boolean withCompression)
{
return curve.createPoint(point.getAffineX(), point.getAffineY(), withCompression);
}
private static ECCurve convertCurve(
EllipticCurve ec)
{
ECField field = ec.getField();
BigInteger a = ec.getA();
BigInteger b = ec.getB();
if (field instanceof ECFieldFp)
{
return new ECCurve.Fp(((ECFieldFp)field).getP(), a, b);
}
else
{
throw new IllegalStateException("not implemented yet!!!");
}
}
}
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