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The Bouncy Castle Java APIs for the OpenPGP Protocol. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.
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.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
* @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
{
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);
}
}