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package org.spongycastle.crypto.util;
import java.io.IOException;
import org.spongycastle.asn1.ASN1Encodable;
import org.spongycastle.asn1.ASN1Integer;
import org.spongycastle.asn1.ASN1OctetString;
import org.spongycastle.asn1.DERNull;
import org.spongycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.spongycastle.asn1.pkcs.RSAPublicKey;
import org.spongycastle.asn1.x509.AlgorithmIdentifier;
import org.spongycastle.asn1.x509.SubjectPublicKeyInfo;
import org.spongycastle.asn1.x9.X962Parameters;
import org.spongycastle.asn1.x9.X9ECParameters;
import org.spongycastle.asn1.x9.X9ECPoint;
import org.spongycastle.asn1.x9.X9ObjectIdentifiers;
import org.spongycastle.crypto.params.AsymmetricKeyParameter;
import org.spongycastle.crypto.params.DSAPublicKeyParameters;
import org.spongycastle.crypto.params.ECDomainParameters;
import org.spongycastle.crypto.params.ECPublicKeyParameters;
import org.spongycastle.crypto.params.RSAKeyParameters;
/**
* Factory to create ASN.1 subject public key info objects from lightweight public keys.
*/
public class SubjectPublicKeyInfoFactory
{
/**
* Create a SubjectPublicKeyInfo public key.
*
* @param publicKey the SubjectPublicKeyInfo encoding
* @return the appropriate key parameter
* @throws java.io.IOException on an error encoding the key
*/
public static SubjectPublicKeyInfo createSubjectPublicKeyInfo(AsymmetricKeyParameter publicKey) throws IOException
{
if (publicKey instanceof RSAKeyParameters)
{
RSAKeyParameters pub = (RSAKeyParameters)publicKey;
return new SubjectPublicKeyInfo(new AlgorithmIdentifier(PKCSObjectIdentifiers.rsaEncryption, DERNull.INSTANCE), new RSAPublicKey(pub.getModulus(), pub.getExponent()));
}
else if (publicKey instanceof DSAPublicKeyParameters)
{
DSAPublicKeyParameters pub = (DSAPublicKeyParameters)publicKey;
return new SubjectPublicKeyInfo(new AlgorithmIdentifier(X9ObjectIdentifiers.id_dsa), new ASN1Integer(pub.getY()));
}
else if (publicKey instanceof ECPublicKeyParameters)
{
ECPublicKeyParameters pub = (ECPublicKeyParameters)publicKey;
ECDomainParameters domainParams = pub.getParameters();
ASN1Encodable params;
// TODO: need to handle named curves
if (domainParams == null)
{
params = new X962Parameters(DERNull.INSTANCE); // Implicitly CA
}
else
{
X9ECParameters ecP = new X9ECParameters(
domainParams.getCurve(),
domainParams.getG(),
domainParams.getN(),
domainParams.getH(),
domainParams.getSeed());
params = new X962Parameters(ecP);
}
ASN1OctetString p = (ASN1OctetString)new X9ECPoint(pub.getQ()).toASN1Primitive();
return new SubjectPublicKeyInfo(new AlgorithmIdentifier(X9ObjectIdentifiers.id_ecPublicKey, params), p.getOctets());
}
else
{
throw new IOException("key parameters not recognised.");
}
}
}
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