org.bouncycastle.openpgp.PGPEncryptedDataList 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.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.bouncycastle.bcpg.BCPGInputStream;
import org.bouncycastle.bcpg.InputStreamPacket;
import org.bouncycastle.bcpg.Packet;
import org.bouncycastle.bcpg.PacketTags;
import org.bouncycastle.bcpg.PublicKeyEncSessionPacket;
import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
import org.bouncycastle.bcpg.SymmetricKeyEncSessionPacket;
import org.bouncycastle.bcpg.UnsupportedPacketVersionException;
import org.bouncycastle.util.Iterable;

/**
 * A holder for a list of PGP encryption method packets and the encrypted data associated with them.
 * 
 * This holder supports reading a sequence of the following encryption methods, followed by an
 * encrypted data packet:
 * 
 * {@link PacketTags#SYMMETRIC_KEY_ENC_SESSION} - produces a {@link PGPPBEEncryptedData}
 * {@link PacketTags#PUBLIC_KEY_ENC_SESSION} - produces a {@link PGPPublicKeyEncryptedData}
 * 
 * 
 * All of the objects returned from this holder share a reference to the same encrypted data input
 * stream, which can only be consumed once.
 * 
 */
public class PGPEncryptedDataList
    implements Iterable
{
    private static final Logger LOG = Logger.getLogger(PGPEncryptedDataList.class.getName());

    List methods = new ArrayList();
    InputStreamPacket data;

    /**
     * Construct an encrypted data packet holder, reading PGP encrypted method packets and an
     * encrypted data packet from a stream.
     * 
     * The first packet in the stream should be one of {@link PacketTags#SYMMETRIC_KEY_ENC_SESSION}
     * or {@link PacketTags#PUBLIC_KEY_ENC_SESSION}.
     * 
     *
     * @param encData a byte array containing an encrypted stream.
     * @throws IOException if an error occurs reading from the PGP input.
     */
    public PGPEncryptedDataList(
        byte[] encData)
        throws IOException
    {
        this(Util.createBCPGInputStream(new ByteArrayInputStream(encData), PacketTags.PUBLIC_KEY_ENC_SESSION, PacketTags.SYMMETRIC_KEY_ENC_SESSION));
    }

    /**
     * Construct an encrypted data packet holder, reading PGP encrypted method packets and an
     * encrypted data packet from a stream.
     * 
     * The first packet in the stream should be one of {@link PacketTags#SYMMETRIC_KEY_ENC_SESSION}
     * or {@link PacketTags#PUBLIC_KEY_ENC_SESSION}.
     * 
     *
     * @param inStream the input stream being read.
     * @throws IOException if an error occurs reading from the PGP input.
     */
    public PGPEncryptedDataList(
        InputStream inStream)
        throws IOException
    {
        this(Util.createBCPGInputStream(inStream, PacketTags.PUBLIC_KEY_ENC_SESSION, PacketTags.SYMMETRIC_KEY_ENC_SESSION));
    }

    /**
     * Construct an encrypted data packet holder, reading PGP encrypted method packets and an
     * encrypted data packet from the stream.
     * 
     * The next packet in the stream should be one of {@link PacketTags#SYMMETRIC_KEY_ENC_SESSION}
     * or {@link PacketTags#PUBLIC_KEY_ENC_SESSION}.
     * 
     *
     * @param pIn the PGP object stream being read.
     * @throws IOException if an error occurs reading from the PGP input.
     */
    public PGPEncryptedDataList(
        BCPGInputStream pIn)
        throws IOException
    {
        List list = new ArrayList();

        while (pIn.nextPacketTag() == PacketTags.PUBLIC_KEY_ENC_SESSION
            || pIn.nextPacketTag() == PacketTags.SYMMETRIC_KEY_ENC_SESSION)
        {
            try
            {
                list.add(pIn.readPacket());
            }
            catch (UnsupportedPacketVersionException e)
            {
                // Skip unknown packet versions
                if (LOG.isLoggable(Level.FINE))
                {
                    LOG.fine("skipping unknown session packet: " + e.getMessage());
                }
            }
        }

        Packet packet = pIn.readPacket();
        if (!(packet instanceof InputStreamPacket))
        {
            throw new IOException("unexpected packet in stream: " + packet);
        }

        data = (InputStreamPacket)packet;

        for (int i = 0; i != list.size(); i++)
        {
            if (list.get(i) instanceof SymmetricKeyEncSessionPacket)
            {
                methods.add(new PGPPBEEncryptedData((SymmetricKeyEncSessionPacket)list.get(i), data));
            }
            else
            {
                methods.add(new PGPPublicKeyEncryptedData((PublicKeyEncSessionPacket)list.get(i), data));
            }
        }
    }

    /**
     * Checks whether the packet is integrity protected.
     *
     * @return true if there is a modification detection code package associated with
     * this stream
     */
    public boolean isIntegrityProtected()
    {
        return data instanceof SymmetricEncIntegrityPacket;
    }

    /**
     * Gets the encryption method object at the specified index.
     *
     * @param index the encryption method to obtain (0 based).
     */
    public PGPEncryptedData get(
        int index)
    {
        return (PGPEncryptedData)methods.get(index);
    }

    /**
     * Gets the number of encryption methods in this list.
     */
    public int size()
    {
        return methods.size();
    }

    /**
     * Returns true iff there are 0 encryption methods in this list.
     */
    public boolean isEmpty()
    {
        return methods.isEmpty();
    }

    /**
     * Returns an iterator over the encryption method objects held in this list, in the order they
     * appeared in the stream they are read from.
     */
    public Iterator getEncryptedDataObjects()
    {
        return methods.iterator();
    }

    /**
     * Support method for Iterable where available.
     */
    public Iterator iterator()
    {
        return getEncryptedDataObjects();
    }

    /**
     * Create a decryption method using a {@link PGPSessionKey}. This method can be used to decrypt messages which do not
     * contain a SKESK or PKESK packet using a session key.
     *
     * @return session key encrypted data
     */
    public PGPSessionKeyEncryptedData extractSessionKeyEncryptedData()
    {
        return new PGPSessionKeyEncryptedData(data);
    }
}