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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.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.bouncycastle.bcpg.InputStreamPacket;
import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.openpgp.operator.PGPDataDecryptor;
import org.bouncycastle.openpgp.operator.PGPDataDecryptorFactory;
import org.bouncycastle.openpgp.operator.PGPDigestCalculator;
import org.bouncycastle.util.Arrays;
/**
* A PGP encrypted data object.
*
* Encrypted data packets are decrypted using a {@link PGPDataDecryptor} obtained from a
* {@link PGPDataDecryptorFactory}.
*
*/
public abstract class PGPEncryptedData
implements SymmetricKeyAlgorithmTags
{
protected static class TruncatedStream
extends InputStream
{
int[] lookAhead = new int[22];
int bufPtr;
InputStream in;
byte[] readBuffer = new byte[8192];
TruncatedStream(
InputStream in)
throws IOException
{
for (int i = 0; i != lookAhead.length; i++)
{
if ((lookAhead[i] = in.read()) < 0)
{
throw new EOFException();
}
}
bufPtr = 0;
this.in = in;
}
public int read()
throws IOException
{
int ch = in.read();
if (ch >= 0)
{
int c = lookAhead[bufPtr];
lookAhead[bufPtr] = ch;
bufPtr = (bufPtr + 1) % lookAhead.length;
return c;
}
return -1;
}
public int read(byte[] b)
throws IOException
{
return read(b, 0, b.length);
}
public int read(byte[] b, int off, int len)
throws IOException
{
// Efficient index check copied from BufferedInputStream
if ((off | len | off + len | b.length - (off + len)) < 0)
{
throw new IndexOutOfBoundsException();
}
else if (len == 0)
{
return 0;
}
// read into our buffer
int maxRead = Math.min(readBuffer.length, len);
int bytesRead = in.read(readBuffer, 0, maxRead);
if (bytesRead < 0)
{
return -1;
}
// Copy lookahead to output
int bytesFromLookahead = Math.min(bytesRead, lookAhead.length);
for (int i = 0; i < bytesFromLookahead; i++)
{
b[off + i] = (byte)lookAhead[(bufPtr + i) % lookAhead.length];
}
// write tail of readBuffer to lookahead
int bufferTail = bytesRead - bytesFromLookahead;
for (int i = bufferTail; i < bytesRead; i++)
{
lookAhead[bufPtr] = readBuffer[i] & 0xff; // we're not at end of file.
bufPtr = (bufPtr + 1) % lookAhead.length;
}
// Copy head of readBuffer to output
if (bufferTail != 0)
{
System.arraycopy(readBuffer, 0, b, off + bytesFromLookahead, bufferTail);
}
return bytesRead;
}
int[] getLookAhead()
{
int[] tmp = new int[lookAhead.length];
int count = 0;
for (int i = bufPtr; i != lookAhead.length; i++)
{
tmp[count++] = lookAhead[i];
}
for (int i = 0; i != bufPtr; i++)
{
tmp[count++] = lookAhead[i];
}
return tmp;
}
}
InputStreamPacket encData;
InputStream encStream;
TruncatedStream truncStream;
PGPDigestCalculator integrityCalculator;
PGPEncryptedData(
InputStreamPacket encData)
{
this.encData = encData;
}
/**
* Return the raw input stream for the data stream.
*
* Note this stream is shared with all other encryption methods in the same
* {@link PGPEncryptedDataList} and with any decryption methods in sub-classes, so consuming
* this stream will affect decryption.
*
*
* @return the encrypted data in this packet.
*/
public InputStream getInputStream()
{
return encData.getInputStream();
}
/**
* 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 (encData instanceof SymmetricEncIntegrityPacket);
}
/**
* Verifies the integrity of the packet against the modification detection code associated with
* it in the stream.
*
* Note: This can only be called after the message has been read.
*
*
* @return true if the message verifies, false otherwise.
* @throws PGPException if the message is not {@link #isIntegrityProtected() integrity
* protected}.
*/
public boolean verify()
throws PGPException, IOException
{
if (!this.isIntegrityProtected())
{
throw new PGPException("data not integrity protected.");
}
//
// make sure we are at the end.
//
while (encStream.read() >= 0)
{
// do nothing
}
//
// process the MDC packet
//
int[] lookAhead = truncStream.getLookAhead();
OutputStream dOut = integrityCalculator.getOutputStream();
dOut.write((byte)lookAhead[0]);
dOut.write((byte)lookAhead[1]);
byte[] digest = integrityCalculator.getDigest();
byte[] streamDigest = new byte[digest.length];
for (int i = 0; i != streamDigest.length; i++)
{
streamDigest[i] = (byte)lookAhead[i + 2];
}
return Arrays.constantTimeAreEqual(digest, streamDigest);
}
/**
* Return the version number of the Encrypted Session Key Packet.
*
* @return version
*/
public int getVersion()
{
throw new UnsupportedOperationException("not supported - override required");
}
/**
* Return the symmetric encryption algorithm that is used by the packet.
*
* @return algorithm
*/
public int getAlgorithm()
{
throw new UnsupportedOperationException("not supported - override required");
}
}