org.bouncycastle.crypto.io.CipherOutputStream Maven / Gradle / Ivy
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package org.bouncycastle.crypto.io;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.StreamCipher;
import org.bouncycastle.crypto.modes.AEADBlockCipher;
/**
* A CipherOutputStream is composed of an OutputStream and a cipher so that write() methods process
* the written data with the cipher, and the output of the cipher is in turn written to the
* underlying OutputStream. The cipher must be fully initialized before being used by a
* CipherInputStream.
*
* For example, if the cipher is initialized for encryption, the CipherOutputStream will encrypt the
* data before writing the encrypted data to the underlying stream.
*/
public class CipherOutputStream
extends FilterOutputStream
{
private BufferedBlockCipher bufferedBlockCipher;
private StreamCipher streamCipher;
private AEADBlockCipher aeadBlockCipher;
private final byte[] oneByte = new byte[1];
private byte[] buf;
/**
* Constructs a CipherOutputStream from an OutputStream and a
* BufferedBlockCipher.
*/
public CipherOutputStream(
OutputStream os,
BufferedBlockCipher cipher)
{
super(os);
this.bufferedBlockCipher = cipher;
}
/**
* Constructs a CipherOutputStream from an OutputStream and a
* BufferedBlockCipher.
*/
public CipherOutputStream(
OutputStream os,
StreamCipher cipher)
{
super(os);
this.streamCipher = cipher;
}
/**
* Constructs a CipherOutputStream from an OutputStream and a AEADBlockCipher.
*/
public CipherOutputStream(OutputStream os, AEADBlockCipher cipher)
{
super(os);
this.aeadBlockCipher = cipher;
}
/**
* Writes the specified byte to this output stream.
*
* @param b the byte.
* @throws java.io.IOException if an I/O error occurs.
*/
public void write(
int b)
throws IOException
{
oneByte[0] = (byte)b;
if (streamCipher != null)
{
out.write(streamCipher.returnByte((byte)b));
}
else
{
write(oneByte, 0, 1);
}
}
/**
* Writes b.length bytes from the specified byte array
* to this output stream.
*
* The write method of
* CipherOutputStream calls the write
* method of three arguments with the three arguments
* b, 0, and b.length.
*
* @param b the data.
* @throws java.io.IOException if an I/O error occurs.
* @see #write(byte[], int, int)
*/
public void write(
byte[] b)
throws IOException
{
write(b, 0, b.length);
}
/**
* Writes len bytes from the specified byte array
* starting at offset off to this output stream.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @throws java.io.IOException if an I/O error occurs.
*/
public void write(
byte[] b,
int off,
int len)
throws IOException
{
ensureCapacity(len, false);
if (bufferedBlockCipher != null)
{
int outLen = bufferedBlockCipher.processBytes(b, off, len, buf, 0);
if (outLen != 0)
{
out.write(buf, 0, outLen);
}
}
else if (aeadBlockCipher != null)
{
int outLen = aeadBlockCipher.processBytes(b, off, len, buf, 0);
if (outLen != 0)
{
out.write(buf, 0, outLen);
}
}
else
{
streamCipher.processBytes(b, off, len, buf, 0);
out.write(buf, 0, len);
}
}
/**
* Ensure the ciphertext buffer has space sufficient to accept an upcoming output.
*
* @param updateSize the size of the pending update.
* @param finalOutput true iff this the cipher is to be finalised.
*/
private void ensureCapacity(int updateSize, boolean finalOutput)
{
int bufLen = updateSize;
if (finalOutput)
{
if (bufferedBlockCipher != null)
{
bufLen = bufferedBlockCipher.getOutputSize(updateSize);
}
else if (aeadBlockCipher != null)
{
bufLen = aeadBlockCipher.getOutputSize(updateSize);
}
}
else
{
if (bufferedBlockCipher != null)
{
bufLen = bufferedBlockCipher.getUpdateOutputSize(updateSize);
}
else if (aeadBlockCipher != null)
{
bufLen = aeadBlockCipher.getUpdateOutputSize(updateSize);
}
}
if ((buf == null) || (buf.length < bufLen))
{
buf = new byte[bufLen];
}
}
/**
* Flushes this output stream by forcing any buffered output bytes
* that have already been processed by the encapsulated cipher object
* to be written out.
*
* Any bytes buffered by the encapsulated cipher
* and waiting to be processed by it will not be written out. For example,
* if the encapsulated cipher is a block cipher, and the total number of
* bytes written using one of the write methods is less than
* the cipher's block size, no bytes will be written out.
*
* @throws java.io.IOException if an I/O error occurs.
*/
public void flush()
throws IOException
{
out.flush();
}
/**
* Closes this output stream and releases any system resources
* associated with this stream.
*
* This method invokes the doFinal method of the encapsulated
* cipher object, which causes any bytes buffered by the encapsulated
* cipher to be processed. The result is written out by calling the
* flush method of this output stream.
*
* This method resets the encapsulated cipher object to its initial state
* and calls the close method of the underlying output
* stream.
*
* @throws java.io.IOException if an I/O error occurs.
* @throws InvalidCipherTextIOException if the data written to this stream was invalid ciphertext
* (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails).
*/
public void close()
throws IOException
{
ensureCapacity(0, true);
IOException error = null;
try
{
if (bufferedBlockCipher != null)
{
int outLen = bufferedBlockCipher.doFinal(buf, 0);
if (outLen != 0)
{
out.write(buf, 0, outLen);
}
}
else if (aeadBlockCipher != null)
{
int outLen = aeadBlockCipher.doFinal(buf, 0);
if (outLen != 0)
{
out.write(buf, 0, outLen);
}
}
else if (streamCipher != null)
{
streamCipher.reset();
}
}
catch (final InvalidCipherTextException e)
{
error = new InvalidCipherTextIOException("Error finalising cipher data", e);
}
catch (Exception e)
{
error = new CipherIOException("Error closing stream: ", e);
}
try
{
flush();
out.close();
}
catch (IOException e)
{
// Invalid ciphertext takes precedence over close error
if (error == null)
{
error = e;
}
}
if (error != null)
{
throw error;
}
}
}