/* ECB.java -- 
   Copyright (C) 2001, 2002, 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
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General Public License for more details.

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Linking this library statically or dynamically with other modules is
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package gnu.javax.crypto.mode;

import gnu.java.security.Registry;
import gnu.javax.crypto.cipher.IBlockCipher;

/**
 * The implementation of the Electronic Codebook mode.
 * <p>
 * The Electronic Codebook (ECB) mode is a confidentiality mode that is defined
 * as follows:
 * <ul>
 * <li>ECB Encryption: C<sub>j</sub> = CIPH<sub>K</sub>(P<sub>j</sub>)
 * for j = 1...n</li>
 * <li>ECB Decryption: P<sub>j</sub> = CIPH<sup>-1</sup><sub>K</sub>(C<sub>j</sub>)
 * for j = 1...n</li>
 * </ul>
 * <p>
 * In ECB encryption, the forward cipher function is applied directly, and
 * independently, to each block of the plaintext. The resulting sequence of
 * output blocks is the ciphertext.
 * <p>
 * In ECB decryption, the inverse cipher function is applied directly, and
 * independently, to each block of the ciphertext. The resulting sequence of
 * output blocks is the plaintext.
 * <p>
 * References:
 * <ol>
 * <li><a
 * href="http://csrc.nist.gov/encryption/modes/Recommendation/Modes01.pdf">
 * Recommendation for Block Cipher Modes of Operation Methods and Techniques</a>,
 * Morris Dworkin.</li>
 * </ol>
 */
public class ECB
    extends BaseMode
    implements Cloneable
{
  /**
   * Trivial package-private constructor for use by the Factory class.
   * 
   * @param underlyingCipher the underlying cipher implementation.
   * @param cipherBlockSize the underlying cipher block size to use.
   */
  ECB(IBlockCipher underlyingCipher, int cipherBlockSize)
  {
    super(Registry.ECB_MODE, underlyingCipher, cipherBlockSize);
  }

  /**
   * Private constructor for cloning purposes.
   * 
   * @param that the mode to clone.
   */
  private ECB(ECB that)
  {
    this((IBlockCipher) that.cipher.clone(), that.cipherBlockSize);
  }

  public Object clone()
  {
    return new ECB(this);
  }

  public void setup()
  {
    if (modeBlockSize != cipherBlockSize)
      throw new IllegalArgumentException(IMode.MODE_BLOCK_SIZE);
  }

  public void teardown()
  {
  }

  public void encryptBlock(byte[] in, int i, byte[] out, int o)
  {
    cipher.encryptBlock(in, i, out, o);
  }

  public void decryptBlock(byte[] in, int i, byte[] out, int o)
  {
    cipher.decryptBlock(in, i, out, o);
  }
}