package gnu.crypto.assembly;
// ----------------------------------------------------------------------------
// $Id: Stage.java,v 1.7 2005/10/06 04:24:13 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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, or (at your option)
// any later version.
//
// GNU Crypto 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 this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, 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.
// ----------------------------------------------------------------------------
import gnu.crypto.mode.IMode;
import java.security.InvalidKeyException;
import java.util.Map;
import java.util.Set;
/**
* <p>A <i>Stage</i> in a Cascade Cipher.</p>
*
* <p>Each stage may be either an implementation of a Block Cipher Mode of
* Operation ({@link IMode}) or another Cascade Cipher ({@link Cascade}). Each
* stage has also a <i>natural</i> operational direction when constructed for
* inclusion within a {@link Cascade}. This <i>natural</i> 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 {@link Direction#FORWARD} direction.</p>
* <pre>
* FORWARD FORWARD
* +------+ +-------+
* | | | |
* | +--in --+ | +--in --+
* ---+ | Stage | | | Stage | +---
* +--out--+ | +--out--+ |
* | | | |
* +-------+ +------+
* </pre>
* <p>The second diagram shows two stages, one in a {@link Direction#FORWARD}
* direction, while the other is wired in a {@link Direction#REVERSED}
* direction.</p>
* <pre>
* FORWARD REVERSED
* +------+ +------+
* | | | |
* | +--in --+ +--in --+ |
* ---+ | Stage | | Stage | +---
* +--out--+ +--out--+
* | |
* +---------------+
* </pre>
*
* @see ModeStage
* @see CascadeStage
* @version $Revision: 1.7 $
*/
public abstract class Stage {
// Constants and variables
// -------------------------------------------------------------------------
public static final String DIRECTION = "gnu.crypto.assembly.stage.direction";
protected Direction forward;
protected Direction wired;
// Constructor(s)
// -------------------------------------------------------------------------
protected Stage(Direction forwardDirection) {
super();
this.forward = forwardDirection;
this.wired = null;
}
// Class methods
// -------------------------------------------------------------------------
public static final Stage
getInstance(IMode mode, Direction forwardDirection) {
return new ModeStage(mode, forwardDirection);
}
public static final Stage
getInstance(Cascade cascade, Direction forwardDirection) {
return new CascadeStage(cascade, forwardDirection);
}
// Instance methods
// -------------------------------------------------------------------------
/**
* Returns the {@link Set} of supported block sizes for this
* <code>Stage</code>. Each element in the returned {@link Set} is an
* instance of {@link Integer}.
*
* @return a {@link Set} of supported block sizes.
*/
public abstract Set blockSizes();
/**
* Initialises the stage for operation with specific characteristics.
*
* @param attributes a set of name-value pairs that describes the desired
* future behaviour of this instance.
* @throws IllegalStateException if the instance is already initialised.
* @throws InvalidKeyException if the key data is invalid.
*/
public void init(Map attributes) throws InvalidKeyException {
if (wired != null) {
throw new IllegalStateException();
}
Direction flow = (Direction) attributes.get(DIRECTION);
if (flow == null) {
flow = Direction.FORWARD;
attributes.put(DIRECTION, flow);
}
initDelegate(attributes);
wired = flow;
}
/**
* Returns the currently set block size for the stage.
*
* @return the current block size for this stage.
* @throws IllegalStateException if the instance is not initialised.
*/
public abstract int currentBlockSize() throws IllegalStateException;
/**
* Resets the stage for re-initialisation and use with other characteristics.
* This method always succeeds.
*/
public void reset() {
resetDelegate();
wired = null;
}
/**
* Processes exactly one block of <i>plaintext</i> (if initialised in the
* {@link Direction#FORWARD} state) or <i>ciphertext</i> (if initialised in
* the {@link Direction#REVERSED} state).
*
* @param in the plaintext.
* @param inOffset index of <code>in</code> from which to start considering
* data.
* @param out the ciphertext.
* @param outOffset index of <code>out</code> from which to store result.
* @throws IllegalStateException if the instance is not initialised.
*/
public void update(byte[] in, int inOffset, byte[] out, int outOffset) {
if (wired == null) {
throw new IllegalStateException();
}
updateDelegate(in, inOffset, out, outOffset);
}
/**
* Conducts a simple <i>correctness</i> 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.
*
* @return <code>true</code> if the implementation passes simple
* <i>correctness</i> tests. Returns <code>false</code> otherwise.
*/
public abstract boolean selfTest();
// abstract methods to be implemented by concrete subclasses ---------------
abstract void initDelegate(Map attributes) throws InvalidKeyException;
abstract void resetDelegate();
abstract void updateDelegate(byte[] in, int inOffset, byte[] out, int outOffset);
}