/* * 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; /** * This abstract class represents the core of all block ciphers. It allows to * intialize the cipher and encrypt/decrypt single blocks. Larger quantities * are handled by modes, which are subclasses of FeedbackCipher. * * @author Gigi Ankeny * @author Jan Luehe * * * @see AESCrypt * @see DESCrypt * @see DESedeCrypt * @see BlowfishCrypt * @see FeedbackCipher */abstract class SymmetricCipher {     SymmetricCipher() {        // empty    }     /**     * Retrieves this cipher's block size.     *     * @return the block size of this cipher     */    abstract int getBlockSize();     /**     * Initializes the cipher in the specified mode with the given key.     *     * @param decrypting flag indicating encryption or decryption     * @param algorithm the algorithm name     * @param key the key     *     * @exception InvalidKeyException if the given key is inappropriate for     * initializing this cipher     */    abstract void init(boolean decrypting, String algorithm, byte[] key)        throws InvalidKeyException;     /**     * Encrypt one cipher block.     *     * <p>The input <code>plain</code>, starting at <code>plainOffset</code>     * and ending at <code>(plainOffset+blockSize-1)</code>, is encrypted.     * The result is stored in <code>cipher</code>, starting at     * <code>cipherOffset</code>.     *     * @param plain the input buffer with the data to be encrypted     * @param plainOffset the offset in <code>plain</code>     * @param cipher the buffer for the encryption result     * @param cipherOffset the offset in <code>cipher</code>     */    abstract void encryptBlock(byte[] plain, int plainOffset,                          byte[] cipher, int cipherOffset);     /**     * Decrypt one cipher block.     *     * <p>The input <code>cipher</code>, starting at <code>cipherOffset</code>     * and ending at <code>(cipherOffset+blockSize-1)</code>, is decrypted.     * The result is stored in <code>plain</code>, starting at     * <code>plainOffset</code>.     *     * @param cipher the input buffer with the data to be decrypted     * @param cipherOffset the offset in <code>cipher</code>     * @param plain the buffer for the decryption result     * @param plainOffset the offset in <code>plain</code>     */    abstract void decryptBlock(byte[] cipher, int cipherOffset,                          byte[] plain, int plainOffset);}