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package org.bouncycastle.cms.jcajce;
import java.io.OutputStream;
import java.security.AlgorithmParameterGenerator;
import java.security.AlgorithmParameters;
import java.security.GeneralSecurityException;
import java.security.Provider;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.RC2ParameterSpec;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.jcajce.io.MacOutputStream;
import org.bouncycastle.operator.GenericKey;
import org.bouncycastle.operator.MacCalculator;
import org.bouncycastle.operator.jcajce.JceGenericKey;
public class JceCMSMacCalculatorBuilder
{
private final ASN1ObjectIdentifier macOID;
private final int keySize;
private EnvelopedDataHelper helper = new EnvelopedDataHelper(new DefaultJcaJceExtHelper());
private SecureRandom random;
public JceCMSMacCalculatorBuilder(ASN1ObjectIdentifier macOID)
{
this(macOID, -1);
}
public JceCMSMacCalculatorBuilder(ASN1ObjectIdentifier macOID, int keySize)
{
this.macOID = macOID;
this.keySize = keySize;
}
public JceCMSMacCalculatorBuilder setProvider(Provider provider)
{
this.helper = new EnvelopedDataHelper(new ProviderJcaJceExtHelper(provider));
return this;
}
public JceCMSMacCalculatorBuilder setProvider(String providerName)
{
this.helper = new EnvelopedDataHelper(new NamedJcaJceExtHelper(providerName));
return this;
}
public JceCMSMacCalculatorBuilder setSecureRandom(SecureRandom random)
{
this.random = random;
return this;
}
public MacCalculator build()
throws CMSException
{
return new CMSMacCalculator(macOID, keySize, random);
}
private class CMSMacCalculator
implements MacCalculator
{
private SecretKey encKey;
private AlgorithmIdentifier algorithmIdentifier;
private Mac mac;
private SecureRandom random;
CMSMacCalculator(ASN1ObjectIdentifier macOID, int keySize, SecureRandom random)
throws CMSException
{
KeyGenerator keyGen = helper.createKeyGenerator(macOID);
if (random == null)
{
random = new SecureRandom();
}
this.random = random;
if (keySize < 0)
{
keyGen.init(random);
}
else
{
keyGen.init(keySize, random);
}
encKey = keyGen.generateKey();
AlgorithmParameterSpec paramSpec = generateParameterSpec(macOID, encKey);
algorithmIdentifier = helper.getAlgorithmIdentifier(macOID, paramSpec);
mac = helper.createContentMac(encKey, algorithmIdentifier);
}
public AlgorithmIdentifier getAlgorithmIdentifier()
{
return algorithmIdentifier;
}
public OutputStream getOutputStream()
{
return new MacOutputStream(mac);
}
public byte[] getMac()
{
return mac.doFinal();
}
public GenericKey getKey()
{
return new JceGenericKey(algorithmIdentifier, encKey);
}
protected AlgorithmParameterSpec generateParameterSpec(ASN1ObjectIdentifier macOID, SecretKey encKey)
throws CMSException
{
try
{
if (macOID.equals(PKCSObjectIdentifiers.RC2_CBC))
{
byte[] iv = new byte[8];
random.nextBytes(iv);
return new RC2ParameterSpec(encKey.getEncoded().length * 8, iv);
}
AlgorithmParameterGenerator pGen = helper.createAlgorithmParameterGenerator(macOID);
AlgorithmParameters p = pGen.generateParameters();
return p.getParameterSpec(IvParameterSpec.class);
}
catch (GeneralSecurityException e)
{
return null;
}
}
}
}
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