llvm-gcc-4.2/libjava/classpath/gnu/javax/crypto/assembly/Stage.java

/* 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
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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
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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
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independent module, the terms and conditions of the license of that
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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
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exception statement from your version.  */


package gnu.javax.crypto.assembly;

import gnu.javax.crypto.mode.IMode;

import java.security.InvalidKeyException;
import java.util.Map;
import java.util.Set;

/**
 * A <i>Stage</i> in a Cascade Cipher.
 * <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.
 * 
 * <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.
 * 
 * <pre>
 *            FORWARD         REVERSED
 *        +------+               +------+
 *        |      |               |      |
 *        |  +--in --+       +--in --+  |
 *     ---+  | Stage |       | Stage |  +---
 *           +--out--+       +--out--+
 *               |               |
 *               +---------------+
 * </pre>
 * 
 * @see ModeStage
 * @see CascadeStage
 */
public abstract class Stage
{
  public static final String DIRECTION = "gnu.crypto.assembly.stage.direction";

  protected Direction forward;

  protected Direction wired;

  protected Stage(Direction forwardDirection)
  {
    super();

    this.forward = forwardDirection;
    this.wired = null;
  }

  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);
  }

  /**
   * 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 void initDelegate(Map attributes) throws InvalidKeyException;

  abstract void resetDelegate();

  abstract void updateDelegate(byte[] in, int inOffset, byte[] out,
                               int outOffset);
}