package org.bouncycastle.openpgp.operator.jcajce;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.PrivateKey;
import java.security.Provider;
import javax.crypto.Cipher;
import org.bouncycastle.jcajce.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.NamedJcaJceHelper;
import org.bouncycastle.jcajce.ProviderJcaJceHelper;
import org.bouncycastle.jce.interfaces.ElGamalKey;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPPrivateKey;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.operator.PGPDataDecryptor;
import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
public class JcePublicKeyDataDecryptorFactoryBuilder
{
private OperatorHelper helper = new OperatorHelper(new DefaultJcaJceHelper());
private OperatorHelper contentHelper = new OperatorHelper(new DefaultJcaJceHelper());
private JcaPGPKeyConverter keyConverter = new JcaPGPKeyConverter();
public JcePublicKeyDataDecryptorFactoryBuilder()
{
}
/**
* Set the provider object to use for creating cryptographic primitives in the resulting factory the builder produces.
*
* @param provider provider object for cryptographic primitives.
* @return the current builder.
*/
public JcePublicKeyDataDecryptorFactoryBuilder setProvider(Provider provider)
{
this.helper = new OperatorHelper(new ProviderJcaJceHelper(provider));
keyConverter.setProvider(provider);
this.contentHelper = helper;
return this;
}
/**
* Set the provider name to use for creating cryptographic primitives in the resulting factory the builder produces.
*
* @param providerName the name of the provider to reference for cryptographic primitives.
* @return the current builder.
*/
public JcePublicKeyDataDecryptorFactoryBuilder setProvider(String providerName)
{
this.helper = new OperatorHelper(new NamedJcaJceHelper(providerName));
keyConverter.setProvider(providerName);
this.contentHelper = helper;
return this;
}
public JcePublicKeyDataDecryptorFactoryBuilder setContentProvider(Provider provider)
{
this.contentHelper = new OperatorHelper(new ProviderJcaJceHelper(provider));
return this;
}
public JcePublicKeyDataDecryptorFactoryBuilder setContentProvider(String providerName)
{
this.contentHelper = new OperatorHelper(new NamedJcaJceHelper(providerName));
return this;
}
public PublicKeyDataDecryptorFactory build(final PrivateKey privKey)
{
return new PublicKeyDataDecryptorFactory()
{
public byte[] recoverSessionData(int keyAlgorithm, BigInteger[] secKeyData)
throws PGPException
{
return decryptSessionData(keyAlgorithm, privKey, secKeyData);
}
public PGPDataDecryptor createDataDecryptor(boolean withIntegrityPacket, int encAlgorithm, byte[] key)
throws PGPException
{
return contentHelper.createDataDecryptor(withIntegrityPacket, encAlgorithm, key);
}
};
}
public PublicKeyDataDecryptorFactory build(final PGPPrivateKey privKey)
{
return new PublicKeyDataDecryptorFactory()
{
public byte[] recoverSessionData(int keyAlgorithm, BigInteger[] secKeyData)
throws PGPException
{
return decryptSessionData(keyAlgorithm, keyConverter.getPrivateKey(privKey), secKeyData);
}
public PGPDataDecryptor createDataDecryptor(boolean withIntegrityPacket, int encAlgorithm, byte[] key)
throws PGPException
{
return contentHelper.createDataDecryptor(withIntegrityPacket, encAlgorithm, key);
}
};
}
private byte[] decryptSessionData(int keyAlgorithm, PrivateKey privKey, BigInteger[] secKeyData)
throws PGPException
{
Cipher c1 = helper.createPublicKeyCipher(keyAlgorithm);
try
{
c1.init(Cipher.DECRYPT_MODE, privKey);
}
catch (InvalidKeyException e)
{
throw new PGPException("error setting asymmetric cipher", e);
}
if (keyAlgorithm == PGPPublicKey.RSA_ENCRYPT
|| keyAlgorithm == PGPPublicKey.RSA_GENERAL)
{
byte[] bi = secKeyData[0].toByteArray();
if (bi[0] == 0)
{
c1.update(bi, 1, bi.length - 1);
}
else
{
c1.update(bi);
}
}
else
{
ElGamalKey k = (ElGamalKey)privKey;
int size = (k.getParameters().getP().bitLength() + 7) / 8;
byte[] tmp = new byte[size];
byte[] bi = secKeyData[0].toByteArray();
if (bi.length > size)
{
c1.update(bi, 1, bi.length - 1);
}
else
{
System.arraycopy(bi, 0, tmp, tmp.length - bi.length, bi.length);
c1.update(tmp);
}
bi = secKeyData[1].toByteArray();
for (int i = 0; i != tmp.length; i++)
{
tmp[i] = 0;
}
if (bi.length > size)
{
c1.update(bi, 1, bi.length - 1);
}
else
{
System.arraycopy(bi, 0, tmp, tmp.length - bi.length, bi.length);
c1.update(tmp);
}
}
byte[] plain;
try
{
plain = c1.doFinal();
}
catch (Exception e)
{
throw new PGPException("exception decrypting session data", e);
}
return plain;
}
}