org.apache.commons.crypto.stream

Class CryptoOutputStream

java.lang.Object

java.io.OutputStream

org.apache.commons.crypto.stream.CryptoOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable, Channel, WritableByteChannel

Direct Known Subclasses:

CtrCryptoOutputStream

public class CryptoOutputStream
extends OutputStream
implements WritableByteChannel

CryptoOutputStream encrypts data and writes to the under layer output. It supports any mode of operations such as AES CBC/CTR/GCM mode in concept. It is not thread-safe.

This class should only be used with blocking sinks. Using this class to wrap a non-blocking sink may lead to high CPU usage.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CryptoOutputStream(Output output, CryptoCipher cipher, int bufferSize, Key key, AlgorithmParameterSpec params) Constructs a CryptoOutputStream.
protected	CryptoOutputStream(OutputStream outputStream, CryptoCipher cipher, int bufferSize, Key key, AlgorithmParameterSpec params) Constructs a CryptoOutputStream.
	CryptoOutputStream(String transformation, Properties properties, OutputStream outputStream, Key key, AlgorithmParameterSpec params) Constructs a CryptoOutputStream.
	CryptoOutputStream(String transformation, Properties properties, WritableByteChannel out, Key key, AlgorithmParameterSpec params) Constructs a CryptoOutputStream.
protected	CryptoOutputStream(WritableByteChannel channel, CryptoCipher cipher, int bufferSize, Key key, AlgorithmParameterSpec params) Constructs a CryptoOutputStream.

Method Summary

Modifier and Type	Method and Description
protected void	checkStream() Checks whether the stream is closed.
void	close() Overrides the OutputStream.close().
protected void	encrypt() Does the encryption, input is inBuffer and output is outBuffer.
protected void	encryptFinal() Does final encryption of the last data.
void	flush() Overrides the OutputStream.flush().
protected void	freeBuffers() Forcibly free the direct buffers.
protected int	getBufferSize() Gets the buffer size.
protected CryptoCipher	getCipher() Gets the internal Cipher.
protected ByteBuffer	getInBuffer() Gets the inBuffer.
protected ByteBuffer	getOutBuffer() Gets the outBuffer.
protected void	initCipher() Initializes the cipher.
boolean	isOpen() Overrides the Channel.isOpen().
void	write(byte[] array, int off, int len) Overrides the OutputStream.write(byte[], int, int).
int	write(ByteBuffer src) Overrides the WritableByteChannel.write(ByteBuffer).
void	write(int b) Overrides the OutputStream.write(byte[]).

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CryptoOutputStream

protected CryptoOutputStream(Output output,
                             CryptoCipher cipher,
                             int bufferSize,
                             Key key,
                             AlgorithmParameterSpec params)
                      throws IOException

Constructs a CryptoOutputStream.

Parameters:

output - the output stream.

cipher - the CryptoCipher instance.

bufferSize - the bufferSize.

key - crypto key for the cipher.

params - the algorithm parameters.

Throws:

IOException - if an I/O error occurs.

CryptoOutputStream

protected CryptoOutputStream(OutputStream outputStream,
                             CryptoCipher cipher,
                             int bufferSize,
                             Key key,
                             AlgorithmParameterSpec params)
                      throws IOException

Constructs a CryptoOutputStream.

Parameters:

outputStream - the output stream.

cipher - the CryptoCipher instance.

bufferSize - the bufferSize.

key - crypto key for the cipher.

params - the algorithm parameters.

Throws:

IOException - if an I/O error occurs.

CryptoOutputStream

public CryptoOutputStream(String transformation,
                          Properties properties,
                          OutputStream outputStream,
                          Key key,
                          AlgorithmParameterSpec params)
                   throws IOException

Constructs a CryptoOutputStream.

Parameters:

transformation - the name of the transformation, e.g., AES/CBC/PKCS5Padding. See the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard transformation names.

properties - The Properties class represents a set of properties.

outputStream - the output stream.

key - crypto key for the cipher.

params - the algorithm parameters.

Throws:

IOException - if an I/O error occurs.

CryptoOutputStream

public CryptoOutputStream(String transformation,
                          Properties properties,
                          WritableByteChannel out,
                          Key key,
                          AlgorithmParameterSpec params)
                   throws IOException

Constructs a CryptoOutputStream.

Parameters:

transformation - the name of the transformation, e.g., AES/CBC/PKCS5Padding. See the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard transformation names.

properties - The Properties class represents a set of properties.

out - the WritableByteChannel instance.

key - crypto key for the cipher.

params - the algorithm parameters.

Throws:

IOException - if an I/O error occurs.

CryptoOutputStream

protected CryptoOutputStream(WritableByteChannel channel,
                             CryptoCipher cipher,
                             int bufferSize,
                             Key key,
                             AlgorithmParameterSpec params)
                      throws IOException

Constructs a CryptoOutputStream.

Parameters:

channel - the WritableByteChannel instance.

cipher - the cipher instance.

bufferSize - the bufferSize.

key - crypto key for the cipher.

params - the algorithm parameters.

Throws:

IOException - if an I/O error occurs.

Method Detail

checkStream

protected void checkStream()
                    throws IOException

Checks whether the stream is closed.

Throws:

IOException - if an I/O error occurs.

close

public void close()
           throws IOException

Overrides the OutputStream.close(). Closes this output stream and releases any system resources associated with this stream.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Overrides:

close in class OutputStream

Throws:

IOException - if an I/O error occurs.

encrypt

protected void encrypt()
                throws IOException

Does the encryption, input is inBuffer and output is outBuffer.

Throws:

IOException - if an I/O error occurs.

encryptFinal

protected void encryptFinal()
                     throws IOException

Does final encryption of the last data.

Throws:

IOException - if an I/O error occurs.

flush

public void flush()
           throws IOException

Overrides the OutputStream.flush(). To flush, we need to encrypt the data in the buffer and write to the underlying stream, then do the flush.

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException - if an I/O error occurs.

freeBuffers

protected void freeBuffers()

Forcibly free the direct buffers.

getBufferSize

protected int getBufferSize()

Gets the buffer size.

Returns:

the buffer size.

getCipher

protected CryptoCipher getCipher()

Gets the internal Cipher.

Returns:

the cipher instance.

getInBuffer

protected ByteBuffer getInBuffer()

Gets the inBuffer.

Returns:

the inBuffer.

getOutBuffer

protected ByteBuffer getOutBuffer()

Gets the outBuffer.

Returns:

the outBuffer.

initCipher

protected void initCipher()
                   throws IOException

Initializes the cipher.

Throws:

IOException - if an I/O error occurs.

isOpen

public boolean isOpen()

Overrides the Channel.isOpen(). Tells whether or not this channel is open.

Specified by:

isOpen in interface Channel

Returns:

true if, and only if, this channel is open

write

public void write(byte[] array,
                  int off,
                  int len)
           throws IOException

Overrides the OutputStream.write(byte[], int, int). Encryption is buffer based. If there is enough room in inBuffer, then write to this buffer. If inBuffer is full, then do encryption and write data to the underlying stream.

Overrides:

write in class OutputStream

Parameters:

array - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

IOException - if an I/O error occurs.

write

public int write(ByteBuffer src)
          throws IOException

Overrides the WritableByteChannel.write(ByteBuffer). Writes a sequence of bytes to this channel from the given buffer.

Specified by:

write in interface WritableByteChannel

Parameters:

src - The buffer from which bytes are to be retrieved.

Returns:

The number of bytes written, possibly zero.

Throws:

IOException - if an I/O error occurs.

write

public void write(int b)
           throws IOException

Overrides the OutputStream.write(byte[]). Writes the specified byte to this output stream.

Specified by:

write in class OutputStream

Parameters:

b - the data.

Throws:

IOException - if an I/O error occurs.