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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.4.
package org.bouncycastle.jcajce.provider.asymmetric.util;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.PrivateKey;
import java.security.PublicKey;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.cryptopro.ECGOST3410NamedCurves;
import org.bouncycastle.asn1.nist.NISTNamedCurves;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.sec.SECNamedCurves;
import org.bouncycastle.asn1.teletrust.TeleTrusTNamedCurves;
import org.bouncycastle.asn1.x9.X962NamedCurves;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.asn1.x9.X962Parameters;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECNamedDomainParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.jce.interfaces.ECPrivateKey;
import org.bouncycastle.jce.interfaces.ECPublicKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jcajce.provider.config.ProviderConfiguration;
/**
* utility class for converting jce/jca ECDSA, ECDH, and ECDHC
* objects into their org.bouncycastle.crypto counterparts.
*/
public class ECUtil
{
/**
* Returns a sorted array of middle terms of the reduction polynomial.
* @param k The unsorted array of middle terms of the reduction polynomial
* of length 1 or 3.
* @return the sorted array of middle terms of the reduction polynomial.
* This array always has length 3.
*/
static int[] convertMidTerms(
int[] k)
{
int[] res = new int[3];
if (k.length == 1)
{
res[0] = k[0];
}
else
{
if (k.length != 3)
{
throw new IllegalArgumentException("Only Trinomials and pentanomials supported");
}
if (k[0] < k[1] && k[0] < k[2])
{
res[0] = k[0];
if (k[1] < k[2])
{
res[1] = k[1];
res[2] = k[2];
}
else
{
res[1] = k[2];
res[2] = k[1];
}
}
else if (k[1] < k[2])
{
res[0] = k[1];
if (k[0] < k[2])
{
res[1] = k[0];
res[2] = k[2];
}
else
{
res[1] = k[2];
res[2] = k[0];
}
}
else
{
res[0] = k[2];
if (k[0] < k[1])
{
res[1] = k[0];
res[2] = k[1];
}
else
{
res[1] = k[1];
res[2] = k[0];
}
}
}
return res;
}
public static ECDomainParameters getDomainParameters(
ProviderConfiguration configuration,
org.bouncycastle.jce.spec.ECParameterSpec params)
{
ECDomainParameters domainParameters;
if (params instanceof ECNamedCurveParameterSpec)
{
ECNamedCurveParameterSpec nParams = (ECNamedCurveParameterSpec)params;
ASN1ObjectIdentifier nameOid = ECUtil.getNamedCurveOid(nParams.getName());
domainParameters = new ECNamedDomainParameters(nameOid, nParams.getCurve(), nParams.getG(), nParams.getN(), nParams.getH(), nParams.getSeed());
}
else if (params == null)
{
org.bouncycastle.jce.spec.ECParameterSpec iSpec = configuration.getEcImplicitlyCa();
domainParameters = new ECDomainParameters(iSpec.getCurve(), iSpec.getG(), iSpec.getN(), iSpec.getH(), iSpec.getSeed());
}
else
{
domainParameters = new ECDomainParameters(params.getCurve(), params.getG(), params.getN(), params.getH(), params.getSeed());
}
return domainParameters;
}
public static ECDomainParameters getDomainParameters(
ProviderConfiguration configuration,
X962Parameters params)
{
ECDomainParameters domainParameters;
if (params.isNamedCurve())
{
ASN1ObjectIdentifier oid = ASN1ObjectIdentifier.getInstance(params.getParameters());
X9ECParameters ecP = ECUtil.getNamedCurveByOid(oid);
domainParameters = new ECNamedDomainParameters(oid, ecP.getCurve(), ecP.getG(), ecP.getN(), ecP.getH(), ecP.getSeed());
}
else if (params.isImplicitlyCA())
{
org.bouncycastle.jce.spec.ECParameterSpec iSpec = configuration.getEcImplicitlyCa();
domainParameters = new ECDomainParameters(iSpec.getCurve(), iSpec.getG(), iSpec.getN(), iSpec.getH(), iSpec.getSeed());
}
else
{
X9ECParameters ecP = X9ECParameters.getInstance(params.getParameters());
domainParameters = new ECDomainParameters(ecP.getCurve(), ecP.getG(), ecP.getN(), ecP.getH(), ecP.getSeed());
}
return domainParameters;
}
public static int getOrderBitLength(ProviderConfiguration configuration, BigInteger order, BigInteger privateValue)
{
if (order == null) // implicitly CA
{
ECParameterSpec implicitCA = configuration.getEcImplicitlyCa();
if (implicitCA == null)
{
return privateValue.bitLength(); // a guess but better than an exception!
}
return implicitCA.getN().bitLength();
}
else
{
return order.bitLength();
}
}
public static AsymmetricKeyParameter generatePublicKeyParameter(
PublicKey key)
throws InvalidKeyException
{
if (key instanceof ECPublicKey && ((ECPublicKey)key).getParameters() != null)
{
ECPublicKey k = (ECPublicKey)key;
ECParameterSpec s = k.getParameters();
return new ECPublicKeyParameters(
k.getQ(),
new ECDomainParameters(s.getCurve(), s.getG(), s.getN(), s.getH(), s.getSeed()));
}
else
{
// see if we can build a key from key.getEncoded()
try
{
byte[] bytes = key.getEncoded();
if (bytes == null)
{
throw new InvalidKeyException("no encoding for EC public key");
}
PublicKey publicKey = BouncyCastleProvider.getPublicKey(SubjectPublicKeyInfo.getInstance(bytes));
if (publicKey instanceof ECPublicKey)
{
return ECUtil.generatePublicKeyParameter(publicKey);
}
}
catch (Exception e)
{
throw new InvalidKeyException("cannot identify EC public key: " + e.toString());
}
}
throw new InvalidKeyException("cannot identify EC public key.");
}
public static AsymmetricKeyParameter generatePrivateKeyParameter(
PrivateKey key)
throws InvalidKeyException
{
if (key instanceof ECPrivateKey)
{
ECPrivateKey k = (ECPrivateKey)key;
ECParameterSpec s = k.getParameters();
if (s == null)
{
s = BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa();
}
return new ECPrivateKeyParameters(
k.getD(),
new ECDomainParameters(s.getCurve(), s.getG(), s.getN(), s.getH(), s.getSeed()));
}
else
{
// see if we can build a key from key.getEncoded()
try
{
byte[] bytes = key.getEncoded();
if (bytes == null)
{
throw new InvalidKeyException("no encoding for EC private key");
}
PrivateKey privateKey = BouncyCastleProvider.getPrivateKey(PrivateKeyInfo.getInstance(bytes));
if (privateKey instanceof ECPrivateKey)
{
return ECUtil.generatePrivateKeyParameter(privateKey);
}
}
catch (Exception e)
{
throw new InvalidKeyException("cannot identify EC private key: " + e.toString());
}
}
throw new InvalidKeyException("can't identify EC private key.");
}
public static ASN1ObjectIdentifier getNamedCurveOid(
String name)
{
ASN1ObjectIdentifier oid = X962NamedCurves.getOID(name);
if (oid == null)
{
oid = SECNamedCurves.getOID(name);
if (oid == null)
{
oid = NISTNamedCurves.getOID(name);
}
if (oid == null)
{
oid = TeleTrusTNamedCurves.getOID(name);
}
if (oid == null)
{
oid = ECGOST3410NamedCurves.getOID(name);
}
}
return oid;
}
public static X9ECParameters getNamedCurveByOid(
ASN1ObjectIdentifier oid)
{
X9ECParameters params = X962NamedCurves.getByOID(oid);
if (params == null)
{
params = SECNamedCurves.getByOID(oid);
if (params == null)
{
params = NISTNamedCurves.getByOID(oid);
}
if (params == null)
{
params = TeleTrusTNamedCurves.getByOID(oid);
}
}
return params;
}
public static String getCurveName(
ASN1ObjectIdentifier oid)
{
String name = X962NamedCurves.getName(oid);
if (name == null)
{
name = SECNamedCurves.getName(oid);
if (name == null)
{
name = NISTNamedCurves.getName(oid);
}
if (name == null)
{
name = TeleTrusTNamedCurves.getName(oid);
}
if (name == null)
{
name = ECGOST3410NamedCurves.getName(oid);
}
}
return name;
}
}
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