org.bouncycastle.openpgp.PGPV3SignatureGenerator Maven / Gradle / Ivy

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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.

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package org.bouncycastle.openpgp;

import java.io.ByteArrayOutputStream;
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.openpgp.operator.PGPContentSigner;
import org.bouncycastle.openpgp.operator.PGPContentSignerBuilder;

/**
 * Generator for old style PGP V3 Signatures.
 */
public class PGPV3SignatureGenerator
    extends PGPDefaultSignatureGenerator
{
    private PGPContentSignerBuilder contentSignerBuilder;
    private PGPContentSigner contentSigner;
//    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 PGPV3SignatureGenerator(
        PGPContentSignerBuilder contentSignerBuilder)
    {
        super(SignaturePacket.VERSION_3);
        this.contentSignerBuilder = contentSignerBuilder;
    }

    /**
     * Initialise the generator for signing.
     *
     * @param signatureType
     * @param key
     * @throws PGPException
     */
    public void init(
        int signatureType,
        PGPPrivateKey key)
        throws PGPException
    {
        if (signatureType == 0xFF)
        {
            throw new PGPException("Illegal signature type 0xFF provided.");
        }
        
        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");
//        }
    }

    /**
     * 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 V3 signature object containing the current signature state.
     *
     * @return PGPSignature
     * @throws PGPException
     */
    public PGPSignature generate()
        throws PGPException
    {
        long creationTime = new Date().getTime() / 1000;

        ByteArrayOutputStream sOut = new ByteArrayOutputStream();

        sOut.write(sigType);
        sOut.write((byte)(creationTime >> 24));
        sOut.write((byte)(creationTime >> 16));
        sOut.write((byte)(creationTime >> 8));
        sOut.write((byte)creationTime);

        byte[] hData = sOut.toByteArray();

        blockUpdate(hData, 0, hData.length);

        MPInteger[] sigValues;
        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(3, contentSigner.getType(), contentSigner.getKeyID(), contentSigner.getKeyAlgorithm(), contentSigner.getHashAlgorithm(), creationTime * 1000, fingerPrint, sigValues));
    }
}