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gnu.javax.crypto.assembly

Class Stage

public abstract class Stage
extends Object
A Stage in a Cascade Cipher.

Each stage may be either an implementation of a Block Cipher Mode of Operation (IMode) or another Cascade Cipher (Cascade). Each stage has also a natural operational direction when constructed for inclusion within a Cascade. This natural direction dictates how data flows from one stage into another when stages are chained together in a cascade. One can think of a stage and its natural direction as the specification of how to wire the stage into the chain. The following diagrams may help understand the paradigme. The first shows two stages chained each with a Direction.FORWARD direction. 

            FORWARD         FORWARD
        +------+       +-------+
        |      |       |       |
        |  +--in --+   |   +--in --+
     ---+  | Stage |   |   | Stage |  +---
           +--out--+   |   +--out--+  |
               |       |       |      |
               +-------+       +------+

The second diagram shows two stages, one in a Direction.FORWARD direction, while the other is wired in a Direction.REVERSED direction. 

            FORWARD         REVERSED
        +------+               +------+
        |      |               |      |
        |  +--in --+       +--in --+  |
     ---+  | Stage |       | Stage |  +---
           +--out--+       +--out--+
               |               |
               +---------------+
See Also:
ModeStage, CascadeStage

Field Summary

static String
DIRECTION
protected Direction
forward
protected Direction
wired

Constructor Summary

Stage(Direction forwardDirection)

Method Summary

abstract Set<E>
blockSizes()
Returns the Set of supported block sizes for this Stage.
abstract int
currentBlockSize()
Returns the currently set block size for the stage.
static Stage
getInstance(Cascade cascade, Direction forwardDirection)
static Stage
getInstance(IMode mode, Direction forwardDirection)
void
init(Map<K,V> attributes)
Initialises the stage for operation with specific characteristics.
void
reset()
Resets the stage for re-initialisation and use with other characteristics.
abstract boolean
selfTest()
Conducts a simple correctness test that consists of basic symmetric encryption / decryption test(s) for all supported block and key sizes of underlying block cipher(s) wrapped by Mode leafs.
void
update(byte[] in, int inOffset, byte[] out, int outOffset)
Processes exactly one block of plaintext (if initialised in the Direction.FORWARD state) or ciphertext (if initialised in the Direction.REVERSED state).

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DIRECTION

public static final String DIRECTION
Field Value:
"gnu.crypto.assembly.stage.direction"

forward

protected Direction forward

wired

protected Direction wired

Constructor Details

Stage

protected Stage(Direction forwardDirection)

Method Details

blockSizes

public abstract Set<E> blockSizes()
Returns the Set of supported block sizes for this Stage. Each element in the returned Set is an instance of Integer.
Returns:
a Set of supported block sizes.

currentBlockSize

public abstract int currentBlockSize()
            throws IllegalStateException
Returns the currently set block size for the stage.
Returns:
the current block size for this stage.
Throws:
IllegalStateException - if the instance is not initialised.

getInstance

public static final Stage getInstance(Cascade cascade,
                                      Direction forwardDirection)

getInstance

public static final Stage getInstance(IMode mode,
                                      Direction forwardDirection)

init

public void init(Map<K,V> attributes)
            throws InvalidKeyException
Initialises the stage for operation with specific characteristics.
Parameters:
attributes - a set of name-value pairs that describes the desired future behaviour of this instance.
Throws:
IllegalStateException - if the instance is already initialised.
InvalidKeyException - if the key data is invalid.

reset

public void reset()
Resets the stage for re-initialisation and use with other characteristics. This method always succeeds.

selfTest

public abstract boolean selfTest()
Conducts a simple correctness test that consists of basic symmetric encryption / decryption test(s) for all supported block and key sizes of underlying block cipher(s) wrapped by Mode leafs. The test also includes one (1) variable key Known Answer Test (KAT) for each block cipher.
Returns:
true if the implementation passes simple correctness tests. Returns false otherwise.

update

public void update(byte[] in,
                   int inOffset,
                   byte[] out,
                   int outOffset)
Processes exactly one block of plaintext (if initialised in the Direction.FORWARD state) or ciphertext (if initialised in the Direction.REVERSED state).
Parameters:
in - the plaintext.
inOffset - index of in from which to start considering data.
out - the ciphertext.
outOffset - index of out from which to store result.
Throws:
IllegalStateException - if the instance is not initialised.
Stage.java -- Copyright (C) 2003, 2006 Free Software Foundation, Inc. This file is a part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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