package org.bouncycastle.openpgp;
import org.bouncycastle.bcpg.BCPGOutputStream;
import org.bouncycastle.bcpg.ContainedPacket;
import org.bouncycastle.bcpg.HashAlgorithmTags;
import org.bouncycastle.bcpg.PacketTags;
import org.bouncycastle.bcpg.PublicKeyEncSessionPacket;
import org.bouncycastle.bcpg.S2K;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.bcpg.SymmetricKeyEncSessionPacket;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.spec.IvParameterSpec;
import java.io.IOException;
import java.io.OutputStream;
import java.math.BigInteger;
import java.security.DigestOutputStream;
import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Provider;
import java.security.Security;
import java.util.ArrayList;
import java.util.List;
/**
* Generator for encrypted objects.
*/
public class PGPEncryptedDataGenerator
implements SymmetricKeyAlgorithmTags, StreamGenerator
{
private BCPGOutputStream pOut;
private CipherOutputStream cOut;
private Cipher c;
private boolean withIntegrityPacket = false;
private boolean oldFormat = false;
private DigestOutputStream digestOut;
private abstract class EncMethod
extends ContainedPacket
{
protected byte[] sessionInfo;
protected int encAlgorithm;
protected Key key;
public abstract void addSessionInfo(
byte[] sessionInfo)
throws Exception;
}
private class PBEMethod
extends EncMethod
{
S2K s2k;
PBEMethod(
int encAlgorithm,
S2K s2k,
Key key)
{
this.encAlgorithm = encAlgorithm;
this.s2k = s2k;
this.key = key;
}
public Key getKey()
{
return key;
}
public void addSessionInfo(
byte[] sessionInfo)
throws Exception
{
String cName = PGPUtil.getSymmetricCipherName(encAlgorithm);
Cipher c = Cipher.getInstance(cName + "/CFB/NoPadding", defProvider);
c.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(new byte[c.getBlockSize()]), rand);
this.sessionInfo = c.doFinal(sessionInfo, 0, sessionInfo.length - 2);
}
public void encode(BCPGOutputStream pOut)
throws IOException
{
SymmetricKeyEncSessionPacket pk = new SymmetricKeyEncSessionPacket(encAlgorithm, s2k, sessionInfo);
pOut.writePacket(pk);
}
}
private class PubMethod
extends EncMethod
{
PGPPublicKey pubKey;
BigInteger[] data;
PubMethod(
PGPPublicKey pubKey)
{
this.pubKey = pubKey;
}
public void addSessionInfo(
byte[] sessionInfo)
throws Exception
{
Cipher c;
switch (pubKey.getAlgorithm())
{
case PGPPublicKey.RSA_ENCRYPT:
case PGPPublicKey.RSA_GENERAL:
c = Cipher.getInstance("RSA/ECB/PKCS1Padding", defProvider);
break;
case PGPPublicKey.ELGAMAL_ENCRYPT:
case PGPPublicKey.ELGAMAL_GENERAL:
c = Cipher.getInstance("ElGamal/ECB/PKCS1Padding", defProvider);
break;
case PGPPublicKey.DSA:
throw new PGPException("Can't use DSA for encryption.");
case PGPPublicKey.ECDSA:
throw new PGPException("Can't use ECDSA for encryption.");
default:
throw new PGPException("unknown asymmetric algorithm: " + pubKey.getAlgorithm());
}
Key key = pubKey.getKey(defProvider);
c.init(Cipher.ENCRYPT_MODE, key, rand);
byte[] encKey = c.doFinal(sessionInfo);
switch (pubKey.getAlgorithm())
{
case PGPPublicKey.RSA_ENCRYPT:
case PGPPublicKey.RSA_GENERAL:
data = new BigInteger[1];
data[0] = new BigInteger(1, encKey);
break;
case PGPPublicKey.ELGAMAL_ENCRYPT:
case PGPPublicKey.ELGAMAL_GENERAL:
byte[] b1 = new byte[encKey.length / 2];
byte[] b2 = new byte[encKey.length / 2];
System.arraycopy(encKey, 0, b1, 0, b1.length);
System.arraycopy(encKey, b1.length, b2, 0, b2.length);
data = new BigInteger[2];
data[0] = new BigInteger(1, b1);
data[1] = new BigInteger(1, b2);
break;
default:
throw new PGPException("unknown asymmetric algorithm: " + encAlgorithm);
}
}
public void encode(BCPGOutputStream pOut)
throws IOException
{
PublicKeyEncSessionPacket pk = new PublicKeyEncSessionPacket(pubKey.getKeyID(), pubKey.getAlgorithm(), data);
pOut.writePacket(pk);
}
}
private List methods = new ArrayList();
private int defAlgorithm;
private SecureRandom rand;
private Provider defProvider;
/**
* Base constructor.
*
* @param encAlgorithm the symmetric algorithm to use.
* @param rand source of randomness
* @param provider the provider to use for encryption algorithms.
*/
public PGPEncryptedDataGenerator(
int encAlgorithm,
SecureRandom rand,
String provider)
{
this(encAlgorithm, rand, Security.getProvider(provider));
}
public PGPEncryptedDataGenerator(
int encAlgorithm,
SecureRandom rand,
Provider provider)
{
this.defAlgorithm = encAlgorithm;
this.rand = rand;
this.defProvider = provider;
}
/**
* Creates a cipher stream which will have an integrity packet
* associated with it.
*
* @param encAlgorithm
* @param withIntegrityPacket
* @param rand
* @param provider
*/
public PGPEncryptedDataGenerator(
int encAlgorithm,
boolean withIntegrityPacket,
SecureRandom rand,
String provider)
{
this(encAlgorithm, withIntegrityPacket, rand, Security.getProvider(provider));
}
public PGPEncryptedDataGenerator(
int encAlgorithm,
boolean withIntegrityPacket,
SecureRandom rand,
Provider provider)
{
this.defAlgorithm = encAlgorithm;
this.rand = rand;
this.defProvider = provider;
this.withIntegrityPacket = withIntegrityPacket;
}
/**
* Base constructor.
*
* @param encAlgorithm the symmetric algorithm to use.
* @param rand source of randomness
* @param oldFormat PGP 2.6.x compatability required.
* @param provider the provider to use for encryption algorithms.
*/
public PGPEncryptedDataGenerator(
int encAlgorithm,
SecureRandom rand,
boolean oldFormat,
String provider)
{
this.defAlgorithm = encAlgorithm;
this.rand = rand;
this.defProvider = Security.getProvider(provider);
this.oldFormat = oldFormat;
}
public PGPEncryptedDataGenerator(
int encAlgorithm,
SecureRandom rand,
boolean oldFormat,
Provider provider)
{
this.defAlgorithm = encAlgorithm;
this.rand = rand;
this.defProvider = provider;
this.oldFormat = oldFormat;
}
/**
* Add a PBE encryption method to the encrypted object.
*
* @param passPhrase
* @throws NoSuchProviderException
* @throws PGPException
*/
public void addMethod(
char[] passPhrase)
throws NoSuchProviderException, PGPException
{
if (defProvider == null)
{
throw new NoSuchProviderException("unable to find provider.");
}
byte[] iv = new byte[8];
rand.nextBytes(iv);
S2K s2k = new S2K(HashAlgorithmTags.SHA1, iv, 0x60);
methods.add(new PBEMethod(defAlgorithm, s2k, PGPUtil.makeKeyFromPassPhrase(defAlgorithm, s2k, passPhrase, defProvider)));
}
/**
* Add a public key encrypted session key to the encrypted object.
*
* @param key
* @throws NoSuchProviderException
* @throws PGPException
*/
public void addMethod(
PGPPublicKey key)
throws NoSuchProviderException, PGPException
{
if (!key.isEncryptionKey())
{
throw new IllegalArgumentException("passed in key not an encryption key!");
}
if (defProvider == null)
{
throw new NoSuchProviderException("unable to find provider.");
}
methods.add(new PubMethod(key));
}
private void addCheckSum(
byte[] sessionInfo)
{
int check = 0;
for (int i = 1; i != sessionInfo.length - 2; i++)
{
check += sessionInfo[i] & 0xff;
}
sessionInfo[sessionInfo.length - 2] = (byte)(check >> 8);
sessionInfo[sessionInfo.length - 1] = (byte)(check);
}
private byte[] createSessionInfo(
int algorithm,
Key key)
{
byte[] keyBytes = key.getEncoded();
byte[] sessionInfo = new byte[keyBytes.length + 3];
sessionInfo[0] = (byte) algorithm;
System.arraycopy(keyBytes, 0, sessionInfo, 1, keyBytes.length);
addCheckSum(sessionInfo);
return sessionInfo;
}
/**
* If buffer is non null stream assumed to be partial, otherwise the
* length will be used to output a fixed length packet.
* <p>
* The stream created can be closed off by either calling close()
* on the stream or close() on the generator. Closing the returned
* stream does not close off the OutputStream parameter out.
*
* @param out
* @param length
* @param buffer
* @return
* @throws IOException
* @throws PGPException
* @throws IllegalStateException
*/
private OutputStream open(
OutputStream out,
long length,
byte[] buffer)
throws IOException, PGPException, IllegalStateException
{
if (cOut != null)
{
throw new IllegalStateException("generator already in open state");
}
if (methods.size() == 0)
{
throw new IllegalStateException("no encryption methods specified");
}
if (defProvider == null)
{
throw new IllegalStateException("provider resolves to null");
}
Key key = null;
pOut = new BCPGOutputStream(out);
if (methods.size() == 1)
{
if (methods.get(0) instanceof PBEMethod)
{
PBEMethod m = (PBEMethod)methods.get(0);
key = m.getKey();
}
else
{
key = PGPUtil.makeRandomKey(defAlgorithm, rand);
byte[] sessionInfo = createSessionInfo(defAlgorithm, key);
PubMethod m = (PubMethod)methods.get(0);
try
{
m.addSessionInfo(sessionInfo);
}
catch (Exception e)
{
throw new PGPException("exception encrypting session key", e);
}
}
pOut.writePacket((ContainedPacket)methods.get(0));
}
else // multiple methods
{
key = PGPUtil.makeRandomKey(defAlgorithm, rand);
byte[] sessionInfo = createSessionInfo(defAlgorithm, key);
for (int i = 0; i != methods.size(); i++)
{
EncMethod m = (EncMethod)methods.get(i);
try
{
m.addSessionInfo(sessionInfo);
}
catch (Exception e)
{
throw new PGPException("exception encrypting session key", e);
}
pOut.writePacket(m);
}
}
String cName = PGPUtil.getSymmetricCipherName(defAlgorithm);
if (cName == null)
{
throw new PGPException("null cipher specified");
}
try
{
if (withIntegrityPacket)
{
c = Cipher.getInstance(cName + "/CFB/NoPadding", defProvider);
}
else
{
c = Cipher.getInstance(cName + "/OpenPGPCFB/NoPadding", defProvider);
}
byte[] iv = new byte[c.getBlockSize()];
c.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(iv), rand);
if (buffer == null)
{
//
// we have to add block size + 2 for the generated IV and + 1 + 22 if integrity protected
//
if (withIntegrityPacket)
{
pOut = new BCPGOutputStream(out, PacketTags.SYM_ENC_INTEGRITY_PRO, length + c.getBlockSize() + 2 + 1 + 22);
pOut.write(1); // version number
}
else
{
pOut = new BCPGOutputStream(out, PacketTags.SYMMETRIC_KEY_ENC, length + c.getBlockSize() + 2, oldFormat);
}
}
else
{
if (withIntegrityPacket)
{
pOut = new BCPGOutputStream(out, PacketTags.SYM_ENC_INTEGRITY_PRO, buffer);
pOut.write(1); // version number
}
else
{
pOut = new BCPGOutputStream(out, PacketTags.SYMMETRIC_KEY_ENC, buffer);
}
}
OutputStream genOut = cOut = new CipherOutputStream(pOut, c);
if (withIntegrityPacket)
{
String digestName = PGPUtil.getDigestName(HashAlgorithmTags.SHA1);
MessageDigest digest = MessageDigest.getInstance(digestName, defProvider);
genOut = digestOut = new DigestOutputStream(cOut, digest);
}
byte[] inLineIv = new byte[c.getBlockSize() + 2];
rand.nextBytes(inLineIv);
inLineIv[inLineIv.length - 1] = inLineIv[inLineIv.length - 3];
inLineIv[inLineIv.length - 2] = inLineIv[inLineIv.length - 4];
genOut.write(inLineIv);
return new WrappedGeneratorStream(genOut, this);
}
catch (Exception e)
{
throw new PGPException("Exception creating cipher", e);
}
}
/**
* Return an outputstream which will encrypt the data as it is written
* to it.
* <p>
* The stream created can be closed off by either calling close()
* on the stream or close() on the generator. Closing the returned
* stream does not close off the OutputStream parameter out.
*
* @param out
* @param length
* @return OutputStream
* @throws IOException
* @throws PGPException
*/
public OutputStream open(
OutputStream out,
long length)
throws IOException, PGPException
{
return this.open(out, length, null);
}
/**
* Return an outputstream which will encrypt the data as it is written
* to it. The stream will be written out in chunks according to the size of the
* passed in buffer.
* <p>
* The stream created can be closed off by either calling close()
* on the stream or close() on the generator. Closing the returned
* stream does not close off the OutputStream parameter out.
* <p>
* <b>Note</b>: if the buffer is not a power of 2 in length only the largest power of 2
* bytes worth of the buffer will be used.
*
* @param out
* @param buffer the buffer to use.
* @return OutputStream
* @throws IOException
* @throws PGPException
*/
public OutputStream open(
OutputStream out,
byte[] buffer)
throws IOException, PGPException
{
return this.open(out, 0, buffer);
}
/**
* Close off the encrypted object - this is equivalent to calling close on the stream
* returned by the open() method.
* <p>
* <b>Note</b>: This does not close the underlying output stream, only the stream on top of it created by the open() method.
* @throws IOException
*/
public void close()
throws IOException
{
if (cOut != null)
{
if (digestOut != null)
{
//
// hand code a mod detection packet
//
BCPGOutputStream bOut = new BCPGOutputStream(digestOut, PacketTags.MOD_DETECTION_CODE, 20);
bOut.flush();
digestOut.flush();
byte[] dig = digestOut.getMessageDigest().digest();
cOut.write(dig);
}
cOut.flush();
try
{
pOut.write(c.doFinal());
pOut.finish();
}
catch (Exception e)
{
throw new IOException(e.toString());
}
cOut = null;
pOut = null;
}
}
}