net.java.truevfs.comp.zip.crypto

Class CipherOutputStream

java.lang.Object

java.io.OutputStream

net.java.truecommons.io.DecoratingOutputStream

net.java.truevfs.comp.zip.crypto.CipherOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

@NotThreadSafe
public final class CipherOutputStream
extends net.java.truecommons.io.DecoratingOutputStream

Similar to javax.crypto.CipherOutputStream with some exceptions:

• This implementation is based on Bouncy Castle's lightweight crypto API and uses a BufferedBlockCipher for ciphering.
• The flush() method just flushes the underlying output stream and has no effect on the cipher.
• For compensation, the finish() method finishes the output (probably producing padding bytes) without closing the output. This can get used in clients to produce a trailer with additional information about the ciphered data (e.g. a MAC).

Author:

Christian Schlichtherle

See Also:

CipherReadOnlyChannel

Field Summary

Fields inherited from class net.java.truecommons.io.DecoratingOutputStream

out

Constructor Summary

Constructors

Constructor and Description
CipherOutputStream(BufferedBlockCipher cipher, OutputStream out) Creates a new cipher output stream.

Method Summary

Modifier and Type	Method and Description
void	close()
void	finish() Finishes and voids this cipher output stream.
void	write(byte[] buf, int off, int len) Ciphers and writes the contents of the given byte array to the underlying output stream.
void	write(int b) Ciphers and writes the given byte to the underlying output stream.

Methods inherited from class net.java.truecommons.io.DecoratingOutputStream

flush, toString, write

Methods inherited from class java.lang.Object

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

Constructor Detail

CipherOutputStream

@CreatesObligation
public CipherOutputStream(BufferedBlockCipher cipher,
                                             @WillCloseWhenClosed
                                             OutputStream out)

Creates a new cipher output stream.

Parameters:

cipher - the block cipher.

out - the output stream.

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class net.java.truecommons.io.DecoratingOutputStream

Throws:

IOException

finish

public void finish()
            throws IOException

Finishes and voids this cipher output stream. Calling this method causes all remaining buffered bytes to get written and padded if necessary. Afterwards, this stream will behave as if it had been closed, although the decorated stream may still be open.

Throws:

IOException - If out or cipher aren't properly initialized, an I/O error occurs or the cipher text is invalid because some required padding is missing.

write

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

Ciphers and writes the contents of the given byte array to the underlying output stream.

Overrides:

write in class net.java.truecommons.io.DecoratingOutputStream

Parameters:

buf - The buffer holding the data to cipher and write.

off - The start offset of the data in the buffer.

len - The number of bytes to cipher and write.

Throws:

IOException - If out or cipher aren't properly initialized, the stream has been closed or an I/O error occured.

write

public void write(int b)
           throws IOException

Ciphers and writes the given byte to the underlying output stream.

Overrides:

write in class net.java.truecommons.io.DecoratingOutputStream

Parameters:

b - The byte to cipher and write.

Throws:

IOException - If out or cipher aren't properly initialized, the stream has been closed or an I/O error occured.