1 /*
   2  * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.crypto.provider;
  27 
  28 import java.security.InvalidKeyException;
  29 
  30 /**
  31  * This abstract class represents the core of all block ciphers. It allows to
  32  * intialize the cipher and encrypt/decrypt single blocks. Larger quantities
  33  * are handled by modes, which are subclasses of FeedbackCipher.
  34  *
  35  * @author Gigi Ankeny
  36  * @author Jan Luehe
  37  *
  38  *
  39  * @see AESCrypt
  40  * @see DESCrypt
  41  * @see DESedeCrypt
  42  * @see BlowfishCrypt
  43  * @see FeedbackCipher
  44  */
  45 abstract class SymmetricCipher {
  46 
  47     SymmetricCipher() {
  48         // empty
  49     }
  50 
  51     /**
  52      * Retrieves this cipher's block size.
  53      *
  54      * @return the block size of this cipher
  55      */
  56     abstract int getBlockSize();
  57 
  58     /**
  59      * Initializes the cipher in the specified mode with the given key.
  60      *
  61      * @param decrypting flag indicating encryption or decryption
  62      * @param algorithm the algorithm name
  63      * @param key the key
  64      *
  65      * @exception InvalidKeyException if the given key is inappropriate for
  66      * initializing this cipher
  67      */
  68     abstract void init(boolean decrypting, String algorithm, byte[] key)
  69         throws InvalidKeyException;
  70 
  71     /**
  72      * Encrypt one cipher block.
  73      *
  74      * <p>The input <code>plain</code>, starting at <code>plainOffset</code>
  75      * and ending at <code>(plainOffset+blockSize-1)</code>, is encrypted.
  76      * The result is stored in <code>cipher</code>, starting at
  77      * <code>cipherOffset</code>.
  78      *
  79      * @param plain the input buffer with the data to be encrypted
  80      * @param plainOffset the offset in <code>plain</code>
  81      * @param cipher the buffer for the encryption result
  82      * @param cipherOffset the offset in <code>cipher</code>
  83      */
  84     abstract void encryptBlock(byte[] plain, int plainOffset,
  85                           byte[] cipher, int cipherOffset);
  86 
  87     /**
  88      * Decrypt one cipher block.
  89      *
  90      * <p>The input <code>cipher</code>, starting at <code>cipherOffset</code>
  91      * and ending at <code>(cipherOffset+blockSize-1)</code>, is decrypted.
  92      * The result is stored in <code>plain</code>, starting at
  93      * <code>plainOffset</code>.
  94      *
  95      * @param cipher the input buffer with the data to be decrypted
  96      * @param cipherOffset the offset in <code>cipher</code>
  97      * @param plain the buffer for the decryption result
  98      * @param plainOffset the offset in <code>plain</code>
  99      */
 100     abstract void decryptBlock(byte[] cipher, int cipherOffset,
 101                           byte[] plain, int plainOffset);
 102 }