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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 1.8. 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.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.math.BigInteger;
import java.util.Date;
import org.bouncycastle.bcpg.MPInteger;
import org.bouncycastle.bcpg.OnePassSignaturePacket;
import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
import org.bouncycastle.bcpg.SignaturePacket;
import org.bouncycastle.bcpg.SignatureSubpacket;
import org.bouncycastle.bcpg.SignatureSubpacketTags;
import org.bouncycastle.bcpg.UserAttributeSubpacket;
import org.bouncycastle.bcpg.sig.IssuerKeyID;
import org.bouncycastle.bcpg.sig.SignatureCreationTime;
import org.bouncycastle.openpgp.operator.PGPContentSigner;
import org.bouncycastle.openpgp.operator.PGPContentSignerBuilder;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.Strings;
/**
* Generator for PGP Signatures.
*/
public class PGPSignatureGenerator
{
private SignatureSubpacket[] unhashed = new SignatureSubpacket[0];
private SignatureSubpacket[] hashed = new SignatureSubpacket[0];
private OutputStream sigOut;
private PGPContentSignerBuilder contentSignerBuilder;
private PGPContentSigner contentSigner;
private int sigType;
private byte lastb;
private int providedKeyAlgorithm = -1;
/**
* Create a signature generator built on the passed in contentSignerBuilder.
*
* @param contentSignerBuilder builder to produce PGPContentSigner objects for generating signatures.
*/
public PGPSignatureGenerator(
PGPContentSignerBuilder contentSignerBuilder)
{
this.contentSignerBuilder = contentSignerBuilder;
}
/**
* Initialise the generator for signing.
*
* @param signatureType
* @param key
* @throws PGPException
*/
public void init(
int signatureType,
PGPPrivateKey key)
throws PGPException
{
contentSigner = contentSignerBuilder.build(signatureType, key);
sigOut = contentSigner.getOutputStream();
sigType = contentSigner.getType();
lastb = 0;
if (providedKeyAlgorithm >= 0 && providedKeyAlgorithm != contentSigner.getKeyAlgorithm())
{
throw new PGPException("key algorithm mismatch");
}
}
public void update(
byte b)
{
if (sigType == PGPSignature.CANONICAL_TEXT_DOCUMENT)
{
if (b == '\r')
{
byteUpdate((byte)'\r');
byteUpdate((byte)'\n');
}
else if (b == '\n')
{
if (lastb != '\r')
{
byteUpdate((byte)'\r');
byteUpdate((byte)'\n');
}
}
else
{
byteUpdate(b);
}
lastb = b;
}
else
{
byteUpdate(b);
}
}
public void update(
byte[] b)
{
this.update(b, 0, b.length);
}
public void update(
byte[] b,
int off,
int len)
{
if (sigType == PGPSignature.CANONICAL_TEXT_DOCUMENT)
{
int finish = off + len;
for (int i = off; i != finish; i++)
{
this.update(b[i]);
}
}
else
{
blockUpdate(b, off, len);
}
}
private void byteUpdate(byte b)
{
try
{
sigOut.write(b);
}
catch (IOException e)
{
throw new PGPRuntimeOperationException(e.getMessage(), e);
}
}
private void blockUpdate(byte[] block, int off, int len)
{
try
{
sigOut.write(block, off, len);
}
catch (IOException e)
{
throw new PGPRuntimeOperationException(e.getMessage(), e);
}
}
public void setHashedSubpackets(
PGPSignatureSubpacketVector hashedPcks)
{
if (hashedPcks == null)
{
hashed = new SignatureSubpacket[0];
return;
}
hashed = hashedPcks.toSubpacketArray();
}
public void setUnhashedSubpackets(
PGPSignatureSubpacketVector unhashedPcks)
{
if (unhashedPcks == null)
{
unhashed = new SignatureSubpacket[0];
return;
}
unhashed = unhashedPcks.toSubpacketArray();
}
/**
* Return the one pass header associated with the current signature.
*
* @param isNested true if the signature is nested, false otherwise.
* @return PGPOnePassSignature
* @throws PGPException
*/
public PGPOnePassSignature generateOnePassVersion(
boolean isNested)
throws PGPException
{
return new PGPOnePassSignature(new OnePassSignaturePacket(sigType, contentSigner.getHashAlgorithm(), contentSigner.getKeyAlgorithm(), contentSigner.getKeyID(), isNested));
}
/**
* Return a signature object containing the current signature state.
*
* @return PGPSignature
* @throws PGPException
*/
public PGPSignature generate()
throws PGPException
{
MPInteger[] sigValues;
int version = 4;
ByteArrayOutputStream sOut = new ByteArrayOutputStream();
SignatureSubpacket[] hPkts, unhPkts;
if (!packetPresent(hashed, SignatureSubpacketTags.CREATION_TIME))
{
hPkts = insertSubpacket(hashed, new SignatureCreationTime(false, new Date()));
}
else
{
hPkts = hashed;
}
if (!packetPresent(hashed, SignatureSubpacketTags.ISSUER_KEY_ID) && !packetPresent(unhashed, SignatureSubpacketTags.ISSUER_KEY_ID))
{
unhPkts = insertSubpacket(unhashed, new IssuerKeyID(false, contentSigner.getKeyID()));
}
else
{
unhPkts = unhashed;
}
try
{
sOut.write((byte)version);
sOut.write((byte)sigType);
sOut.write((byte)contentSigner.getKeyAlgorithm());
sOut.write((byte)contentSigner.getHashAlgorithm());
ByteArrayOutputStream hOut = new ByteArrayOutputStream();
for (int i = 0; i != hPkts.length; i++)
{
hPkts[i].encode(hOut);
}
byte[] data = hOut.toByteArray();
sOut.write((byte)(data.length >> 8));
sOut.write((byte)data.length);
sOut.write(data);
}
catch (IOException e)
{
throw new PGPException("exception encoding hashed data.", e);
}
byte[] hData = sOut.toByteArray();
sOut.write((byte)version);
sOut.write((byte)0xff);
sOut.write((byte)(hData.length >> 24));
sOut.write((byte)(hData.length >> 16));
sOut.write((byte)(hData.length >> 8));
sOut.write((byte)(hData.length));
byte[] trailer = sOut.toByteArray();
blockUpdate(trailer, 0, trailer.length);
if (contentSigner.getKeyAlgorithm() == PublicKeyAlgorithmTags.RSA_SIGN
|| contentSigner.getKeyAlgorithm() == PublicKeyAlgorithmTags.RSA_GENERAL) // an RSA signature
{
sigValues = new MPInteger[1];
sigValues[0] = new MPInteger(new BigInteger(1, contentSigner.getSignature()));
}
else if (contentSigner.getKeyAlgorithm() == PublicKeyAlgorithmTags.EDDSA_LEGACY)
{
byte[] enc = contentSigner.getSignature();
sigValues = new MPInteger[]{
new MPInteger(new BigInteger(1, Arrays.copyOfRange(enc, 0, enc.length / 2))),
new MPInteger(new BigInteger(1, Arrays.copyOfRange(enc, enc.length / 2, enc.length)))
};
}
else
{
sigValues = PGPUtil.dsaSigToMpi(contentSigner.getSignature());
}
byte[] digest = contentSigner.getDigest();
byte[] fingerPrint = new byte[2];
fingerPrint[0] = digest[0];
fingerPrint[1] = digest[1];
return new PGPSignature(new SignaturePacket(sigType, contentSigner.getKeyID(), contentSigner.getKeyAlgorithm(), contentSigner.getHashAlgorithm(), hPkts, unhPkts, fingerPrint, sigValues));
}
/**
* Generate a certification for the passed in id and key.
*
* @param id the id we are certifying against the public key.
* @param pubKey the key we are certifying against the id.
* @return the certification.
* @throws PGPException
*/
public PGPSignature generateCertification(
String id,
PGPPublicKey pubKey)
throws PGPException
{
updateWithPublicKey(pubKey);
//
// hash in the id
//
updateWithIdData(0xb4, Strings.toUTF8ByteArray(id));
return this.generate();
}
/**
* Generate a certification for the passed in userAttributes
* @param userAttributes the id we are certifying against the public key.
* @param pubKey the key we are certifying against the id.
* @return the certification.
* @throws PGPException
*/
public PGPSignature generateCertification(
PGPUserAttributeSubpacketVector userAttributes,
PGPPublicKey pubKey)
throws PGPException
{
updateWithPublicKey(pubKey);
//
// hash in the attributes
//
try
{
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
UserAttributeSubpacket[] packets = userAttributes.toSubpacketArray();
for (int i = 0; i != packets.length; i++)
{
packets[i].encode(bOut);
}
updateWithIdData(0xd1, bOut.toByteArray());
}
catch (IOException e)
{
throw new PGPException("cannot encode subpacket array", e);
}
return this.generate();
}
/**
* Generate a certification for the passed in key against the passed in
* master key.
*
* @param masterKey the key we are certifying against.
* @param pubKey the key we are certifying.
* @return the certification.
* @throws PGPException
*/
public PGPSignature generateCertification(
PGPPublicKey masterKey,
PGPPublicKey pubKey)
throws PGPException
{
updateWithPublicKey(masterKey);
updateWithPublicKey(pubKey);
return this.generate();
}
/**
* Generate a certification, such as a revocation, for the passed in key.
*
* @param pubKey the key we are certifying.
* @return the certification.
* @throws PGPException
*/
public PGPSignature generateCertification(
PGPPublicKey pubKey)
throws PGPException
{
if ((sigType == PGPSignature.SUBKEY_REVOCATION || sigType == PGPSignature.SUBKEY_BINDING) && !pubKey.isMasterKey())
{
throw new IllegalArgumentException("certifications involving subkey requires public key of revoking key as well.");
}
updateWithPublicKey(pubKey);
return this.generate();
}
private byte[] getEncodedPublicKey(
PGPPublicKey pubKey)
throws PGPException
{
byte[] keyBytes;
try
{
keyBytes = pubKey.publicPk.getEncodedContents();
}
catch (IOException e)
{
throw new PGPException("exception preparing key.", e);
}
return keyBytes;
}
private boolean packetPresent(
SignatureSubpacket[] packets,
int type)
{
for (int i = 0; i != packets.length; i++)
{
if (packets[i].getType() == type)
{
return true;
}
}
return false;
}
private SignatureSubpacket[] insertSubpacket(
SignatureSubpacket[] packets,
SignatureSubpacket subpacket)
{
SignatureSubpacket[] tmp = new SignatureSubpacket[packets.length + 1];
tmp[0] = subpacket;
System.arraycopy(packets, 0, tmp, 1, packets.length);
return tmp;
}
private void updateWithIdData(int header, byte[] idBytes)
{
this.update((byte)header);
this.update((byte)(idBytes.length >> 24));
this.update((byte)(idBytes.length >> 16));
this.update((byte)(idBytes.length >> 8));
this.update((byte)(idBytes.length));
this.update(idBytes);
}
private void updateWithPublicKey(PGPPublicKey key)
throws PGPException
{
byte[] keyBytes = getEncodedPublicKey(key);
this.update((byte)0x99);
this.update((byte)(keyBytes.length >> 8));
this.update((byte)(keyBytes.length));
this.update(keyBytes);
}
}
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