/* IBlockCipherSpi.java -- 
   Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

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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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permission to link this library with independent modules to produce an
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package gnu.javax.crypto.cipher;

import java.security.InvalidKeyException;
import java.util.Iterator;

/**
 * Package-private interface exposing mandatory methods to be implemented by
 * concrete {@link BaseCipher} sub-classes.
 */
interface IBlockCipherSpi
    extends Cloneable
{
  /**
   * Returns an {@link Iterator} over the supported block sizes. Each element
   * returned by this object is a {@link java.lang.Integer}.
   * 
   * @return an <code>Iterator</code> over the supported block sizes.
   */
  Iterator blockSizes();

  /**
   * Returns an {@link Iterator} over the supported key sizes. Each element
   * returned by this object is a {@link java.lang.Integer}.
   * 
   * @return an <code>Iterator</code> over the supported key sizes.
   */
  Iterator keySizes();

  /**
   * Expands a user-supplied key material into a session key for a designated
   * <i>block size</i>.
   * 
   * @param k the user-supplied key material.
   * @param bs the desired block size in bytes.
   * @return an Object encapsulating the session key.
   * @exception IllegalArgumentException if the block size is invalid.
   * @exception InvalidKeyException if the key data is invalid.
   */
  Object makeKey(byte[] k, int bs) throws InvalidKeyException;

  /**
   * Encrypts exactly one block of plaintext.
   * 
   * @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 the
   *          result.
   * @param k the session key to use.
   * @param bs the block size to use.
   * @exception IllegalArgumentException if the block size is invalid.
   * @exception ArrayIndexOutOfBoundsException if there is not enough room in
   *              either the plaintext or ciphertext buffers.
   */
  void encrypt(byte[] in, int inOffset, byte[] out, int outOffset, Object k,
               int bs);

  /**
   * Decrypts exactly one block of ciphertext.
   * 
   * @param in the ciphertext.
   * @param inOffset index of <code>in</code> from which to start considering
   *          data.
   * @param out the plaintext.
   * @param outOffset index of <code>out</code> from which to store the
   *          result.
   * @param k the session key to use.
   * @param bs the block size to use.
   * @exception IllegalArgumentException if the block size is invalid.
   * @exception ArrayIndexOutOfBoundsException if there is not enough room in
   *              either the plaintext or ciphertext buffers.
   */
  void decrypt(byte[] in, int inOffset, byte[] out, int outOffset, Object k,
               int bs);

  /**
   * A <i>correctness</i> test that consists of basic symmetric encryption /
   * decryption test(s) for all supported block and key sizes, as well as one
   * (1) variable key Known Answer Test (KAT).
   * 
   * @return <code>true</code> if the implementation passes simple
   *         <i>correctness</i> tests. Returns <code>false</code> otherwise.
   */
  boolean selfTest();
}