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The Bouncy Castle Java API for handling the OpenPGP protocol. This jar contains the OpenPGP API for JDK 1.8 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
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package org.bouncycastle.openpgp.operator.jcajce;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.bcpg.AEADAlgorithmTags;
import org.bouncycastle.bcpg.AEADEncDataPacket;
import org.bouncycastle.bcpg.AEADUtils;
import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.bcpg.SymmetricKeyUtils;
import org.bouncycastle.crypto.digests.SHA256Digest;
import org.bouncycastle.crypto.generators.HKDFBytesGenerator;
import org.bouncycastle.crypto.params.HKDFParameters;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPSessionKey;
import org.bouncycastle.openpgp.PGPUtil;
import org.bouncycastle.openpgp.operator.PGPDataDecryptor;
import org.bouncycastle.openpgp.operator.PGPDigestCalculator;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.Exceptions;
import org.bouncycastle.util.Pack;
import org.bouncycastle.util.io.Streams;
class JceAEADUtil
{
private final OperatorHelper helper;
public JceAEADUtil(OperatorHelper helper)
{
this.helper = helper;
}
/**
* Generate a nonce by xor-ing the given iv with the chunk index.
*
* @param iv initialization vector
* @param chunkIndex chunk index
* @return nonce
*/
protected static byte[] getNonce(byte[] iv, long chunkIndex)
{
byte[] nonce = Arrays.clone(iv);
xorChunkId(nonce, chunkIndex);
return nonce;
}
/**
* XOR the byte array with the chunk index in-place.
*
* @param nonce byte array
* @param chunkIndex chunk index
*/
protected static void xorChunkId(byte[] nonce, long chunkIndex)
{
int index = nonce.length - 8;
nonce[index++] ^= (byte)(chunkIndex >> 56);
nonce[index++] ^= (byte)(chunkIndex >> 48);
nonce[index++] ^= (byte)(chunkIndex >> 40);
nonce[index++] ^= (byte)(chunkIndex >> 32);
nonce[index++] ^= (byte)(chunkIndex >> 24);
nonce[index++] ^= (byte)(chunkIndex >> 16);
nonce[index++] ^= (byte)(chunkIndex >> 8);
nonce[index] ^= (byte)(chunkIndex);
}
/**
* Calculate an actual chunk length from the encoded chunk size.
*
* @param chunkSize encoded chunk size
* @return decoded length
*/
protected static long getChunkLength(int chunkSize)
{
return 1L << (chunkSize + 6);
}
/**
* Derive a message key and IV from the given session key.
* The result is two byte arrays containing the key bytes and the IV.
*
* @param aeadAlgo AEAD algorithm
* @param cipherAlgo symmetric cipher algorithm
* @param sessionKey session key
* @param salt salt
* @param hkdfInfo HKDF info
* @return message key and separate IV
* @throws PGPException
*/
static byte[][] deriveMessageKeyAndIv(int aeadAlgo, int cipherAlgo, byte[] sessionKey, byte[] salt, byte[] hkdfInfo)
throws PGPException
{
// TODO: needs to be JCA based. KeyGenerator
int keyLen = SymmetricKeyUtils.getKeyLengthInOctets(cipherAlgo);
int ivLen = AEADUtils.getIVLength(aeadAlgo);
byte[] messageKeyAndIv = generateHKDFBytes(sessionKey, salt, hkdfInfo, keyLen + ivLen - 8);
return new byte[][]{Arrays.copyOfRange(messageKeyAndIv, 0, keyLen), Arrays.copyOfRange(messageKeyAndIv, keyLen, keyLen + ivLen)};
}
static byte[] generateHKDFBytes(byte[] sessionKey, byte[] salt, byte[] hkdfInfo, int len)
{
HKDFParameters hkdfParameters = new HKDFParameters(sessionKey, salt, hkdfInfo);
HKDFBytesGenerator hkdfGen = new HKDFBytesGenerator(new SHA256Digest());
hkdfGen.init(hkdfParameters);
byte[] messageKeyAndIv = new byte[len];
hkdfGen.generateBytes(messageKeyAndIv, 0, messageKeyAndIv.length);
return messageKeyAndIv;
}
/**
* Create a {@link PGPDataDecryptor} for decrypting AEAD encrypted OpenPGP v5 data packets.
*
* @param aeadEncDataPacket AEAD encrypted data packet
* @param sessionKey session key to decrypt the data
* @return decryptor
* @throws PGPException
*/
PGPDataDecryptor createOpenPgpV5DataDecryptor(AEADEncDataPacket aeadEncDataPacket,
PGPSessionKey sessionKey)
throws PGPException
{
final int aeadAlgorithm = aeadEncDataPacket.getAEADAlgorithm();
final byte[] iv = aeadEncDataPacket.getIV();
final int chunkSize = aeadEncDataPacket.getChunkSize();
final int encAlgorithm = sessionKey.getAlgorithm();
final byte[] key = sessionKey.getKey();
final byte[] aaData = aeadEncDataPacket.getAAData();
try
{
final SecretKey secretKey = new SecretKeySpec(key, PGPUtil.getSymmetricCipherName(encAlgorithm));
final Cipher c = createAEADCipher(encAlgorithm, aeadAlgorithm);
return new PGPDataDecryptor()
{
public InputStream getInputStream(InputStream in)
{
try
{
return new JceAEADUtil.PGPAeadInputStream(true, in, c, secretKey, iv, encAlgorithm, aeadAlgorithm, chunkSize, aaData);
}
catch (IOException e)
{
throw Exceptions.illegalStateException("unable to open stream: " + e.getMessage(), e);
}
}
public int getBlockSize()
{
return c.getBlockSize();
}
public PGPDigestCalculator getIntegrityCalculator()
{
return new SHA1PGPDigestCalculator();
}
};
}
catch (PGPException e)
{
throw e;
}
catch (Exception e)
{
throw new PGPException("Exception creating cipher", e);
}
}
/**
* Create a {@link PGPDataDecryptor} for decrypting AEAD encrypted OpenPGP v6 data.
*
* @param seipd version 2 SEIPD packet
* @param sessionKey session key to decrypt the data
* @return decryptor
* @throws PGPException
*/
PGPDataDecryptor createOpenPgpV6DataDecryptor(SymmetricEncIntegrityPacket seipd,
PGPSessionKey sessionKey)
throws PGPException
{
final int cipherAlgo = seipd.getCipherAlgorithm();
final int aeadAlgo = seipd.getAeadAlgorithm();
final int chunkSize = seipd.getChunkSize();
final byte[] salt = seipd.getSalt();
final byte[] aaData = seipd.getAAData();
final byte[][] messageKeyAndIv = deriveMessageKeyAndIv(aeadAlgo, cipherAlgo, sessionKey.getKey(), salt, aaData);
final byte[] messageKey = messageKeyAndIv[0];
final byte[] iv = messageKeyAndIv[1];
try
{
final SecretKey secretKey = new SecretKeySpec(messageKey, PGPUtil.getSymmetricCipherName(cipherAlgo));
final Cipher c = createAEADCipher(cipherAlgo, aeadAlgo);
return new PGPDataDecryptor()
{
public InputStream getInputStream(InputStream in)
{
try
{
return new JceAEADUtil.PGPAeadInputStream(false, in, c, secretKey, iv, cipherAlgo, aeadAlgo, chunkSize, aaData);
}
catch (IOException e)
{
throw Exceptions.illegalStateException("unable to open stream: " + e.getMessage(), e);
}
}
public int getBlockSize()
{
return c.getBlockSize();
}
public PGPDigestCalculator getIntegrityCalculator()
{
return new SHA1PGPDigestCalculator();
}
};
}
catch (PGPException e)
{
throw e;
}
catch (Exception e)
{
throw new PGPException("Exception creating cipher", e);
}
}
Cipher createAEADCipher(int encAlgorithm, int aeadAlgorithm)
throws PGPException
{
if (encAlgorithm != SymmetricKeyAlgorithmTags.AES_128
&& encAlgorithm != SymmetricKeyAlgorithmTags.AES_192
&& encAlgorithm != SymmetricKeyAlgorithmTags.AES_256
&& encAlgorithm != SymmetricKeyAlgorithmTags.CAMELLIA_128
&& encAlgorithm != SymmetricKeyAlgorithmTags.CAMELLIA_192
&& encAlgorithm != SymmetricKeyAlgorithmTags.CAMELLIA_256)
{
// Block Cipher must work on 16 byte blocks
throw new PGPException("AEAD only supported for AES and Camellia" + " based algorithms");
}
String mode;
switch (aeadAlgorithm)
{
case AEADAlgorithmTags.EAX:
mode = "EAX";
break;
case AEADAlgorithmTags.OCB:
mode = "OCB";
break;
case AEADAlgorithmTags.GCM:
mode = "GCM";
break;
default:
throw new PGPException("encountered unknown AEAD algorithm: " + aeadAlgorithm);
}
String cName = PGPUtil.getSymmetricCipherName(encAlgorithm)
+ "/" + mode + "/NoPadding";
return helper.createCipher(cName);
}
static class PGPAeadInputStream
extends InputStream
{
private final InputStream in;
private final byte[] buf;
private final Cipher c;
private final SecretKey secretKey;
private final byte[] aaData;
private final byte[] iv;
private final int chunkLength;
private final int aeadTagLength;
private byte[] data;
private int dataOff;
private long chunkIndex = 0;
private long totalBytes = 0;
private boolean v5StyleAEAD;
/**
* InputStream for decrypting AEAD encrypted data.
*
* @param isV5AEAD AEAD flavour (OpenPGP v5 or v6)
* @param in underlying input stream
* @param c AEAD cipher
* @param secretKey secret key
* @param iv initialization vector
* @param encAlgorithm encryption algorithm
* @param aeadAlgorithm AEAD algorithm
* @param chunkSize chunk size of the AEAD encryption
* @param aaData associated data
* @throws IOException
*/
public PGPAeadInputStream(boolean isV5AEAD, InputStream in,
Cipher c,
SecretKey secretKey,
byte[] iv,
int encAlgorithm,
int aeadAlgorithm,
int chunkSize,
byte[] aaData)
throws IOException
{
this.v5StyleAEAD = isV5AEAD;
this.in = in;
this.iv = iv;
this.chunkLength = (int)getChunkLength(chunkSize);
this.aeadTagLength = AEADUtils.getAuthTagLength(aeadAlgorithm);
this.buf = new byte[chunkLength + aeadTagLength + aeadTagLength]; // allow room for chunk tag and message tag
this.c = c;
this.secretKey = secretKey;
this.aaData = aaData;
// prime with 2 * tag len bytes.
Streams.readFully(in, buf, 0, aeadTagLength + aeadTagLength);
// load the first block
this.data = readBlock();
this.dataOff = 0;
}
public int read()
throws IOException
{
if (data != null && dataOff == data.length)
{
this.data = readBlock();
this.dataOff = 0;
}
if (this.data == null)
{
return -1;
}
return data[dataOff++] & 0xff;
}
public int read(byte[] b, int off, int len)
throws IOException
{
if (data != null && dataOff == data.length)
{
this.data = readBlock();
this.dataOff = 0;
}
if (this.data == null)
{
return -1;
}
int supplyLen = Math.min(len, available());
System.arraycopy(data, dataOff, b, off, supplyLen);
dataOff += supplyLen;
return supplyLen;
}
public long skip(long n)
throws IOException
{
if (n <= 0)
{
return 0;
}
int skip = (int)Math.min(n, available());
dataOff += skip;
return skip;
}
public int available()
throws IOException
{
if (data != null && dataOff == data.length)
{
this.data = readBlock();
this.dataOff = 0;
}
if (this.data == null)
{
return -1;
}
return data.length - dataOff;
}
private byte[] readBlock()
throws IOException
{
// we initialise with the first 16 bytes as there is an additional 16 bytes following
// the last chunk (which may not be the exact chunklength).
int dataLen = Streams.readFully(in, buf, aeadTagLength + aeadTagLength, chunkLength);
if (dataLen == 0)
{
return null;
}
byte[] adata = new byte[v5StyleAEAD ? 13 : aaData.length];
System.arraycopy(aaData, 0, adata, 0, aaData.length);
if (v5StyleAEAD)
{
xorChunkId(adata, chunkIndex);
}
byte[] decData;
try
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.DECRYPT_MODE, getNonce(iv, chunkIndex), 128, adata);
decData = c.doFinal(buf, 0, dataLen + aeadTagLength);
}
catch (GeneralSecurityException e)
{
throw new IOException("exception processing chunk " + chunkIndex + ": " + e.getMessage());
}
totalBytes += decData.length;
chunkIndex++;
System.arraycopy(buf, dataLen + aeadTagLength, buf, 0, aeadTagLength); // copy back the "tag"
if (dataLen != chunkLength) // it's our last block
{
adata = PGPAeadOutputStream.getAdata(v5StyleAEAD, aaData, chunkIndex, totalBytes);
try
{
if (v5StyleAEAD)
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.DECRYPT_MODE, getNonce(iv, chunkIndex), 128, Arrays.concatenate(adata, Pack.longToBigEndian(totalBytes)));
}
else
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.DECRYPT_MODE, getNonce(iv, chunkIndex), 128, adata);
}
c.doFinal(buf, 0, aeadTagLength); // check final tag
}
catch (GeneralSecurityException e)
{
throw new IOException("exception processing final tag: " + e.getMessage());
}
}
else
{
Streams.readFully(in, buf, aeadTagLength, aeadTagLength); // read the next tag bytes
}
return decData;
}
}
static class PGPAeadOutputStream
extends OutputStream
{
private final boolean isV5AEAD;
private final OutputStream out;
private final byte[] data;
private final Cipher c;
private final SecretKey secretKey;
private final byte[] aaData;
private final byte[] iv;
private final int chunkLength;
private int dataOff;
private long chunkIndex = 0;
private long totalBytes = 0;
/**
* OutputStream for AEAD encryption.
*
* @param isV5AEAD isV5AEAD of AEAD (OpenPGP v5 or v6)
* @param out underlying OutputStream
* @param c AEAD cipher
* @param secretKey secret key
* @param iv initialization vector
* @param encAlgorithm encryption algorithm
* @param aeadAlgorithm AEAD algorithm
* @param chunkSize chunk size of the AEAD algorithm
*/
public PGPAeadOutputStream(boolean isV5AEAD,
OutputStream out,
Cipher c,
SecretKey secretKey,
byte[] iv,
int encAlgorithm,
int aeadAlgorithm,
int chunkSize)
{
this.isV5AEAD = isV5AEAD;
this.out = out;
this.iv = iv;
this.chunkLength = (int)getChunkLength(chunkSize);
this.data = new byte[chunkLength];
this.c = c;
this.secretKey = secretKey;
this.aaData = createAAD(isV5AEAD, encAlgorithm, aeadAlgorithm, chunkSize);
}
/**
* Create the associated data for the AEAD encryption.
* Since the associated data array differs between OpenPGP v5 and v6, we need to know the flavour.
*
* @param isV5AEAD true if flavour of AEAD OpenPGP v5
* @param encAlgorithm symmetric encryption algorithm
* @param aeadAlgorithm AEAD algorithm
* @param chunkSize chunk size
* @return associated data
*/
private byte[] createAAD(boolean isV5AEAD, int encAlgorithm, int aeadAlgorithm, int chunkSize)
{
if (isV5AEAD)
{
return AEADEncDataPacket.createAAData(AEADEncDataPacket.VERSION_1,
encAlgorithm, aeadAlgorithm, chunkSize);
}
else
{
return SymmetricEncIntegrityPacket.createAAData(SymmetricEncIntegrityPacket.VERSION_2,
encAlgorithm, aeadAlgorithm, chunkSize);
}
}
public void write(int b)
throws IOException
{
if (dataOff == data.length)
{
writeBlock();
}
data[dataOff++] = (byte)b;
}
public void write(byte[] b, int off, int len)
throws IOException
{
if (dataOff == data.length)
{
writeBlock();
}
if (len < data.length - dataOff)
{
System.arraycopy(b, off, data, dataOff, len);
dataOff += len;
}
else
{
int gap = data.length - dataOff;
System.arraycopy(b, off, data, dataOff, gap);
dataOff += gap;
writeBlock();
len -= gap;
off += gap;
while (len >= data.length)
{
System.arraycopy(b, off, data, 0, data.length);
dataOff = data.length;
writeBlock();
len -= data.length;
off += data.length;
}
if (len > 0)
{
System.arraycopy(b, off, data, 0, len);
dataOff = len;
}
}
}
public void close()
throws IOException
{
finish();
}
private void writeBlock()
throws IOException
{
byte[] adata = isV5AEAD ? new byte[13] : new byte[aaData.length];
System.arraycopy(aaData, 0, adata, 0, aaData.length);
if (isV5AEAD)
{
xorChunkId(adata, chunkIndex);
}
try
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.ENCRYPT_MODE, getNonce(iv, chunkIndex), 128, adata);
out.write(c.doFinal(data, 0, dataOff));
}
catch (GeneralSecurityException e)
{
throw new IOException("exception processing chunk " + chunkIndex + ": " + e.getMessage());
}
totalBytes += dataOff;
chunkIndex++;
dataOff = 0;
}
private void finish()
throws IOException
{
if (dataOff > 0)
{
writeBlock();
}
byte[] adata = getAdata(isV5AEAD, aaData, chunkIndex, totalBytes);
try
{
if (isV5AEAD)
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.ENCRYPT_MODE, getNonce(iv, chunkIndex), 128, Arrays.concatenate(adata, Pack.longToBigEndian(totalBytes)));
}
else
{
JceAEADCipherUtil.setUpAeadCipher(c, secretKey, Cipher.ENCRYPT_MODE, getNonce(iv, chunkIndex), 128, adata);
}
out.write(c.doFinal(aaData, 0, 0)); // output final tag
}
catch (GeneralSecurityException e)
{
throw new IOException("exception processing final tag: " + e.getMessage());
}
out.close();
}
private static byte[] getAdata(boolean isV5AEAD, byte[] aaData, long chunkIndex, long totalBytes)
{
byte[] adata;
if (isV5AEAD)
{
adata = new byte[13];
System.arraycopy(aaData, 0, adata, 0, aaData.length);
xorChunkId(adata, chunkIndex);
}
else
{
adata = new byte[aaData.length + 8];
System.arraycopy(aaData, 0, adata, 0, aaData.length);
System.arraycopy(Pack.longToBigEndian(totalBytes), 0, adata, aaData.length, 8);
}
return adata;
}
}
}
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