| /* |
| * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.crypto.provider; |
| |
| import java.security.InvalidKeyException; |
| import javax.crypto.IllegalBlockSizeException; |
| |
| /** |
| * This class represents a block cipher in one of its modes. It wraps |
| * a SymmetricCipher maintaining the mode state and providing |
| * the capability to encrypt amounts of data larger than a single block. |
| * |
| * @author Jan Luehe |
| * @see ElectronicCodeBook |
| * @see CipherBlockChaining |
| * @see CipherFeedback |
| * @see OutputFeedback |
| * @see PCBC |
| */ |
| abstract class FeedbackCipher { |
| |
| // the embedded block cipher |
| final SymmetricCipher embeddedCipher; |
| |
| // the block size of the embedded block cipher |
| final int blockSize; |
| |
| // the initialization vector |
| byte[] iv; |
| |
| FeedbackCipher(SymmetricCipher embeddedCipher) { |
| this.embeddedCipher = embeddedCipher; |
| blockSize = embeddedCipher.getBlockSize(); |
| } |
| |
| final SymmetricCipher getEmbeddedCipher() { |
| return embeddedCipher; |
| } |
| |
| /** |
| * Gets the block size of the embedded cipher. |
| * |
| * @return the block size of the embedded cipher |
| */ |
| final int getBlockSize() { |
| return blockSize; |
| } |
| |
| /** |
| * Gets the name of the feedback mechanism |
| * |
| * @return the name of the feedback mechanism |
| */ |
| abstract String getFeedback(); |
| |
| /** |
| * Save the current content of this cipher. |
| */ |
| abstract void save(); |
| |
| /** |
| * Restores the content of this cipher to the previous saved one. |
| */ |
| abstract void restore(); |
| |
| /** |
| * Initializes the cipher in the specified mode with the given key |
| * and iv. |
| * |
| * @param decrypting flag indicating encryption or decryption mode |
| * @param algorithm the algorithm name (never null) |
| * @param key the key (never null) |
| * @param iv the iv (either null or blockSize bytes long) |
| * |
| * @exception InvalidKeyException if the given key is inappropriate for |
| * initializing this cipher |
| */ |
| abstract void init(boolean decrypting, String algorithm, byte[] key, |
| byte[] iv) throws InvalidKeyException; |
| |
| /** |
| * Gets the initialization vector. |
| * |
| * @return the initialization vector |
| */ |
| final byte[] getIV() { |
| return iv; |
| } |
| |
| /** |
| * Resets the iv to its original value. |
| * This is used when doFinal is called in the Cipher class, so that the |
| * cipher can be reused (with its original iv). |
| */ |
| abstract void reset(); |
| |
| /** |
| * Performs encryption operation. |
| * |
| * <p>The input <code>plain</code>, starting at <code>plainOffset</code> |
| * and ending at <code>(plainOffset+plainLen-1)</code>, is encrypted. |
| * The result is stored in <code>cipher</code>, starting at |
| * <code>cipherOffset</code>. |
| * |
| * <p>The subclass that implements Cipher should ensure that |
| * <code>init</code> has been called before this method is called. |
| * |
| * @param plain the input buffer with the data to be encrypted |
| * @param plainOffset the offset in <code>plain</code> |
| * @param plainLen the length of the input data |
| * @param cipher the buffer for the encryption result |
| * @param cipherOffset the offset in <code>cipher</code> |
| */ |
| abstract void encrypt(byte[] plain, int plainOffset, int plainLen, |
| byte[] cipher, int cipherOffset); |
| /** |
| * Performs encryption operation for the last time. |
| * |
| * <p>NOTE: For cipher feedback modes which does not perform |
| * special handling for the last few blocks, this is essentially |
| * the same as <code>encrypt(...)</code>. Given most modes do |
| * not do special handling, the default impl for this method is |
| * to simply call <code>encrypt(...)</code>. |
| * |
| * @param plain the input buffer with the data to be encrypted |
| * @param plainOffset the offset in <code>plain</code> |
| * @param plainLen the length of the input data |
| * @param cipher the buffer for the encryption result |
| * @param cipherOffset the offset in <code>cipher</code> |
| */ |
| void encryptFinal(byte[] plain, int plainOffset, int plainLen, |
| byte[] cipher, int cipherOffset) |
| throws IllegalBlockSizeException { |
| encrypt(plain, plainOffset, plainLen, cipher, cipherOffset); |
| } |
| /** |
| * Performs decryption operation. |
| * |
| * <p>The input <code>cipher</code>, starting at <code>cipherOffset</code> |
| * and ending at <code>(cipherOffset+cipherLen-1)</code>, is decrypted. |
| * The result is stored in <code>plain</code>, starting at |
| * <code>plainOffset</code>. |
| * |
| * <p>The subclass that implements Cipher should ensure that |
| * <code>init</code> has been called before this method is called. |
| * |
| * @param cipher the input buffer with the data to be decrypted |
| * @param cipherOffset the offset in <code>cipher</code> |
| * @param cipherLen the length of the input data |
| * @param plain the buffer for the decryption result |
| * @param plainOffset the offset in <code>plain</code> |
| */ |
| abstract void decrypt(byte[] cipher, int cipherOffset, int cipherLen, |
| byte[] plain, int plainOffset); |
| |
| /** |
| * Performs decryption operation for the last time. |
| * |
| * <p>NOTE: For cipher feedback modes which does not perform |
| * special handling for the last few blocks, this is essentially |
| * the same as <code>encrypt(...)</code>. Given most modes do |
| * not do special handling, the default impl for this method is |
| * to simply call <code>decrypt(...)</code>. |
| * |
| * @param cipher the input buffer with the data to be decrypted |
| * @param cipherOffset the offset in <code>cipher</code> |
| * @param cipherLen the length of the input data |
| * @param plain the buffer for the decryption result |
| * @param plainOffset the offset in <code>plain</code> |
| */ |
| void decryptFinal(byte[] cipher, int cipherOffset, int cipherLen, |
| byte[] plain, int plainOffset) |
| throws IllegalBlockSizeException { |
| decrypt(cipher, cipherOffset, cipherLen, plain, plainOffset); |
| } |
| } |