package org.spongycastle.cms.jcajce;
import java.security.Key;
import java.security.Provider;
import javax.crypto.SecretKey;
import org.spongycastle.asn1.x509.AlgorithmIdentifier;
import org.spongycastle.cms.CMSException;
import org.spongycastle.cms.KEKRecipient;
import org.spongycastle.operator.OperatorException;
import org.spongycastle.operator.SymmetricKeyUnwrapper;
public abstract class JceKEKRecipient
implements KEKRecipient
{
private SecretKey recipientKey;
protected EnvelopedDataHelper helper = new EnvelopedDataHelper(new DefaultJcaJceExtHelper());
protected EnvelopedDataHelper contentHelper = helper;
public JceKEKRecipient(SecretKey recipientKey)
{
this.recipientKey = recipientKey;
}
/**
* Set the provider to use for key recovery and content processing.
*
* @param provider provider to use.
* @return this recipient.
*/
public JceKEKRecipient setProvider(Provider provider)
{
this.helper = new EnvelopedDataHelper(new ProviderJcaJceExtHelper(provider));
this.contentHelper = helper;
return this;
}
/**
* Set the provider to use for key recovery and content processing.
*
* @param providerName the name of the provider to use.
* @return this recipient.
*/
public JceKEKRecipient setProvider(String providerName)
{
this.helper = new EnvelopedDataHelper(new NamedJcaJceExtHelper(providerName));
this.contentHelper = helper;
return this;
}
/**
* Set the provider to use for content processing.
*
* @param provider the provider to use.
* @return this recipient.
*/
public JceKEKRecipient setContentProvider(Provider provider)
{
this.contentHelper = new EnvelopedDataHelper(new ProviderJcaJceExtHelper(provider));
return this;
}
/**
* Set the provider to use for content processing.
*
* @param providerName the name of the provider to use.
* @return this recipient.
*/
public JceKEKRecipient setContentProvider(String providerName)
{
this.contentHelper = new EnvelopedDataHelper(new NamedJcaJceExtHelper(providerName));
return this;
}
protected Key extractSecretKey(AlgorithmIdentifier keyEncryptionAlgorithm, AlgorithmIdentifier contentEncryptionAlgorithm, byte[] encryptedContentEncryptionKey)
throws CMSException
{
SymmetricKeyUnwrapper unwrapper = helper.createSymmetricUnwrapper(keyEncryptionAlgorithm, recipientKey);
try
{
return helper.getJceKey(contentEncryptionAlgorithm.getAlgorithm(), unwrapper.generateUnwrappedKey(contentEncryptionAlgorithm, encryptedContentEncryptionKey));
}
catch (OperatorException e)
{
throw new CMSException("exception unwrapping key: " + e.getMessage(), e);
}
}
}