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The Bouncy Castle Java API for handling the OpenPGP protocol. This jar contains the OpenPGP API for JDK 1.5 to JDK 1.7. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
package org.bouncycastle.openpgp;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.SecureRandom;
import java.util.Date;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.bcpg.ArmoredInputStream;
import org.bouncycastle.bcpg.BCPGInputStream;
import org.bouncycastle.bcpg.HashAlgorithmTags;
import org.bouncycastle.bcpg.MPInteger;
import org.bouncycastle.bcpg.PacketTags;
import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.encoders.Base64;
import org.bouncycastle.util.encoders.DecoderException;
/**
* PGP utilities.
*/
public class PGPUtil
implements HashAlgorithmTags
{
private static String defProvider = "BC";
/**
* Return an appropriate name for the hash algorithm represented by the passed
* in hash algorithm ID number.
*
* @param hashAlgorithm the algorithm ID for a hash algorithm.
* @return a String representation of the hash name.
*/
public static String getDigestName(
int hashAlgorithm)
throws PGPException
{
switch (hashAlgorithm)
{
case HashAlgorithmTags.SHA1:
return "SHA1";
case HashAlgorithmTags.MD2:
return "MD2";
case HashAlgorithmTags.MD5:
return "MD5";
case HashAlgorithmTags.RIPEMD160:
return "RIPEMD160";
case HashAlgorithmTags.SHA256:
return "SHA256";
case HashAlgorithmTags.SHA384:
return "SHA384";
case HashAlgorithmTags.SHA512:
return "SHA512";
case HashAlgorithmTags.SHA224:
return "SHA224";
case HashAlgorithmTags.TIGER_192:
return "TIGER";
default:
throw new PGPException("unknown hash algorithm tag in getDigestName: " + hashAlgorithm);
}
}
/**
* Return an appropriate name for the signature algorithm represented by the passed
* in public key and hash algorithm ID numbers.
*
* @param keyAlgorithm the algorithm ID for the public key algorithm used in the signature.
* @param hashAlgorithm the algorithm ID for the hash algorithm used.
* @return a String representation of the signature name.
*/
public static String getSignatureName(
int keyAlgorithm,
int hashAlgorithm)
throws PGPException
{
String encAlg;
switch (keyAlgorithm)
{
case PublicKeyAlgorithmTags.RSA_GENERAL:
case PublicKeyAlgorithmTags.RSA_SIGN:
encAlg = "RSA";
break;
case PublicKeyAlgorithmTags.DSA:
encAlg = "DSA";
break;
case PublicKeyAlgorithmTags.ELGAMAL_ENCRYPT: // in some malformed cases.
case PublicKeyAlgorithmTags.ELGAMAL_GENERAL:
encAlg = "ElGamal";
break;
default:
throw new PGPException("unknown algorithm tag in signature:" + keyAlgorithm);
}
return getDigestName(hashAlgorithm) + "with" + encAlg;
}
/**
* Return an appropriate name for the symmetric algorithm represented by the passed
* in symmetric algorithm ID number.
*
* @param algorithm the algorithm ID for a symmetric cipher.
* @return a String representation of the cipher name.
*/
public static String getSymmetricCipherName(
int algorithm)
{
switch (algorithm)
{
case SymmetricKeyAlgorithmTags.NULL:
return null;
case SymmetricKeyAlgorithmTags.TRIPLE_DES:
return "DESEDE";
case SymmetricKeyAlgorithmTags.IDEA:
return "IDEA";
case SymmetricKeyAlgorithmTags.CAST5:
return "CAST5";
case SymmetricKeyAlgorithmTags.BLOWFISH:
return "Blowfish";
case SymmetricKeyAlgorithmTags.SAFER:
return "SAFER";
case SymmetricKeyAlgorithmTags.DES:
return "DES";
case SymmetricKeyAlgorithmTags.AES_128:
return "AES";
case SymmetricKeyAlgorithmTags.AES_192:
return "AES";
case SymmetricKeyAlgorithmTags.AES_256:
return "AES";
case SymmetricKeyAlgorithmTags.CAMELLIA_128:
return "Camellia";
case SymmetricKeyAlgorithmTags.CAMELLIA_192:
return "Camellia";
case SymmetricKeyAlgorithmTags.CAMELLIA_256:
return "Camellia";
case SymmetricKeyAlgorithmTags.TWOFISH:
return "Twofish";
default:
throw new IllegalArgumentException("unknown symmetric algorithm: " + algorithm);
}
}
/**
* Return the JCA/JCE provider that will be used by factory classes in situations where a
* provider must be determined on the fly.
*
* @return the name of the default provider.
* @deprecated unused
*/
public static String getDefaultProvider()
{
// TODO: no longer used.
return defProvider;
}
/**
* Set the provider to be used by the package when it is necessary to find one on the fly.
*
* @param provider the name of the JCA/JCE provider to use by default.
* @deprecated unused
*/
public static void setDefaultProvider(
String provider)
{
defProvider = provider;
}
static MPInteger[] dsaSigToMpi(
byte[] encoding)
throws PGPException
{
ASN1InputStream aIn = new ASN1InputStream(encoding);
ASN1Integer i1;
ASN1Integer i2;
try
{
ASN1Sequence s = ASN1Sequence.getInstance(aIn.readObject());
i1 = ASN1Integer.getInstance(s.getObjectAt(0));
i2 = ASN1Integer.getInstance(s.getObjectAt(1));
}
catch (IOException e)
{
throw new PGPException("exception decoding signature", e);
}
catch (IllegalArgumentException e)
{
throw new PGPException("exception decoding signature", e);
}
MPInteger[] values = new MPInteger[2];
values[0] = new MPInteger(i1.getValue());
values[1] = new MPInteger(i2.getValue());
return values;
}
/**
* Return true if the byte[] blob probably represents key ring data.
* @return true if data likely represents a key ring stream.
*/
public static boolean isKeyRing(byte[] blob)
throws IOException
{
BCPGInputStream bIn = new BCPGInputStream(new ByteArrayInputStream(blob));
int tag = bIn.nextPacketTag();
return tag == PacketTags.PUBLIC_KEY || tag == PacketTags.PUBLIC_SUBKEY
|| tag == PacketTags.SECRET_KEY || tag == PacketTags.SECRET_KEY;
}
/**
* Return true if the byte[] blob probably represents key box data.
* @return true if data likely represents a key box stream.
*/
public static boolean isKeyBox(byte[] data)
throws IOException
{
if (data.length < 12)
{
return false;
}
InputStream bIn = new ByteArrayInputStream(data);
// skip size and headers
for (int i = 0; i != 8; i++)
{
bIn.read();
}
return bIn.read() == 'K' && bIn.read() == 'B' && bIn.read() == 'X' && bIn.read() == 'f';
}
/**
* Generates a random key for a {@link SymmetricKeyAlgorithmTags symmetric encryption algorithm}
* .
*
* @param algorithm the symmetric key algorithm identifier.
* @param random a source of random data.
* @return a key of the length required by the specified encryption algorithm.
* @throws PGPException if the encryption algorithm is unknown.
*/
public static byte[] makeRandomKey(
int algorithm,
SecureRandom random)
throws PGPException
{
int keySize = 0;
switch (algorithm)
{
case SymmetricKeyAlgorithmTags.TRIPLE_DES:
keySize = 192;
break;
case SymmetricKeyAlgorithmTags.IDEA:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.CAST5:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.BLOWFISH:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.SAFER:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.DES:
keySize = 64;
break;
case SymmetricKeyAlgorithmTags.AES_128:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.AES_192:
keySize = 192;
break;
case SymmetricKeyAlgorithmTags.AES_256:
keySize = 256;
break;
case SymmetricKeyAlgorithmTags.CAMELLIA_128:
keySize = 128;
break;
case SymmetricKeyAlgorithmTags.CAMELLIA_192:
keySize = 192;
break;
case SymmetricKeyAlgorithmTags.CAMELLIA_256:
keySize = 256;
break;
case SymmetricKeyAlgorithmTags.TWOFISH:
keySize = 256;
break;
default:
throw new PGPException("unknown symmetric algorithm: " + algorithm);
}
byte[] keyBytes = new byte[(keySize + 7) / 8];
random.nextBytes(keyBytes);
return keyBytes;
}
/**
* Write out the contents of the provided file as a literal data packet.
*
* @param out the stream to write the literal data to.
* @param fileType the {@link PGPLiteralData} type to use for the file data.
* @param file the file to write the contents of.
* @throws IOException if an error occurs reading the file or writing to the output stream.
*/
public static void writeFileToLiteralData(
OutputStream out,
char fileType,
File file)
throws IOException
{
PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
OutputStream pOut = lData.open(out, fileType, file);
pipeFileContents(file, pOut, 32768);
}
/**
* Write out the contents of the provided file as a literal data packet in partial packet
* format.
*
* @param out the stream to write the literal data to.
* @param fileType the {@link PGPLiteralData} type to use for the file data.
* @param file the file to write the contents of.
* @param buffer buffer to be used to chunk the file into partial packets.
* @throws IOException if an error occurs reading the file or writing to the output stream.
* @see PGPLiteralDataGenerator#open(OutputStream, char, String, Date, byte[])
*/
public static void writeFileToLiteralData(
OutputStream out,
char fileType,
File file,
byte[] buffer)
throws IOException
{
PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
OutputStream pOut = lData.open(out, fileType, file.getName(), new Date(file.lastModified()), buffer);
pipeFileContents(file, pOut, buffer.length);
}
private static void pipeFileContents(File file, OutputStream pOut, int bufferSize)
throws IOException
{
byte[] buf = new byte[bufferSize];
FileInputStream in = new FileInputStream(file);
try
{
int len;
while ((len = in.read(buf)) > 0)
{
pOut.write(buf, 0, len);
}
pOut.close();
}
finally
{
Arrays.fill(buf, (byte)0);
try
{
in.close();
}
catch (IOException ignored)
{
// ignore...
}
}
}
private static final int READ_AHEAD = 60;
private static boolean isPossiblyBase64(
int ch)
{
return (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')
|| (ch >= '0' && ch <= '9') || (ch == '+') || (ch == '/')
|| (ch == '\r') || (ch == '\n');
}
/**
* Obtains a stream that can be used to read PGP data from the provided stream.
*
* If the initial bytes of the underlying stream are binary PGP encodings, then the stream will
* be returned directly, otherwise an {@link ArmoredInputStream} is used to wrap the provided
* stream and remove ASCII-Armored encoding.
*
*
* @param in the stream to be checked and possibly wrapped.
* @return a stream that will return PGP binary encoded data.
* @throws IOException if an error occurs reading the stream, or initialising the
* {@link ArmoredInputStream}.
*/
public static InputStream getDecoderStream(
InputStream in)
throws IOException
{
if (!in.markSupported())
{
in = new BufferedInputStreamExt(in);
}
in.mark(READ_AHEAD);
int ch = in.read();
if ((ch & 0x80) != 0)
{
in.reset();
return in;
}
else
{
if (!isPossiblyBase64(ch))
{
in.reset();
return new ArmoredInputStream(in);
}
byte[] buf = new byte[READ_AHEAD];
int count = 1;
int index = 1;
buf[0] = (byte)ch;
while (count != READ_AHEAD && (ch = in.read()) >= 0)
{
if (!isPossiblyBase64(ch))
{
in.reset();
return new ArmoredInputStream(in);
}
if (ch != '\n' && ch != '\r')
{
buf[index++] = (byte)ch;
}
count++;
}
in.reset();
//
// nothing but new lines, little else, assume regular armoring
//
if (count < 4)
{
return new ArmoredInputStream(in);
}
//
// test our non-blank data
//
byte[] firstBlock = new byte[8];
System.arraycopy(buf, 0, firstBlock, 0, firstBlock.length);
try
{
byte[] decoded = Base64.decode(firstBlock);
//
// it's a base64 PGP block.
//
if ((decoded[0] & 0x80) != 0)
{
return new ArmoredInputStream(in, false);
}
return new ArmoredInputStream(in);
}
catch (DecoderException e)
{
throw new IOException(e.getMessage());
}
}
}
static class BufferedInputStreamExt
extends BufferedInputStream
{
BufferedInputStreamExt(InputStream input)
{
super(input);
}
public synchronized int available()
throws IOException
{
int result = super.available();
if (result < 0)
{
result = Integer.MAX_VALUE;
}
return result;
}
}
}