ccs.crypt
Class CipherOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          ccs.crypt.CipherOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable

Direct Known Subclasses:

AbstractBlockCipherOutputStream

public abstract class CipherOutputStream
extends java.io.FilterOutputStream

Field Summary

protected long	plainlen The plaintext length for this stream.
protected byte[]	temp8 An 8-byte scratch space.

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

CipherOutputStream(java.io.OutputStream os, long plainlen)
Construct a CipherOutputStream.

Method Summary

void	close()
abstract void	finish() Completes the encryption but does not close the underlying stream.
void	flush() Flushes at least the underlying stream.
abstract void	write(byte[] b, int off, int len)
void	write(int b) writes a single byte.

Methods inherited from class java.io.FilterOutputStream

write

Methods inherited from class java.lang.Object

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

Field Detail

temp8

protected byte[] temp8

An 8-byte scratch space. Useful for a) buffering single-byte reads; b) working with packed longs.

See Also:

Unsigned.writePacked(java.io.OutputStream, long, byte[])

plainlen

protected long plainlen

The plaintext length for this stream. It is up to subclasses to work with this appropriately.

Constructor Detail

CipherOutputStream

public CipherOutputStream(java.io.OutputStream os,
                          long plainlen)

Construct a CipherOutputStream. NOTE: this ctor does *not* set the dam, that's up to subclasses. Recommended strategy: on first write (set a flag to determine this) set the dam to the ciphertext length, then write away. This is less friendly than it could be - wrong-length writes will throw in a non-obvious place - but it's the only way to avoid scribbling on the underlying stream.

Method Detail

write

public void write(int b)
           throws java.io.IOException

writes a single byte. This by default calls the method of three arguments; this is inefficient and should be avoided where efficiency is an issue.

Overrides:

write in class java.io.FilterOutputStream

Parameters:

b - The value (in the range 0-255) to be written

Throws:

java.io.IOException - if an error occurs.

flush

public void flush()
           throws java.io.IOException

Flushes at least the underlying stream. However, some subclasses (especially block ciphers) may cache plaintext in internal buffers for encryption en bloc; this cached plaintext might not be flushed. Use finish() to ensure that all plaintext has been encrypted and written.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.FilterOutputStream

Throws:

java.io.IOException - If thrown by the underlying stream.

write

public abstract void write(byte[] b,
                           int off,
                           int len)
                    throws java.io.IOException

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

finish

public abstract void finish()
                     throws java.io.IOException

Completes the encryption but does not close the underlying stream.

Throws:

java.io.IOException - if the finish failed for some reason.

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.FilterOutputStream

Throws:

java.io.IOException