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/* * 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 class implements the Triple DES algorithm (DES encryption, followed by * DES decryption, followed by DES encryption) on a byte array of size * <code>DES_BLOCK_SIZE</code>. Each DES operation has its own key. * * @author Gigi Ankeny * @author Jan Luehe * * * @see DESConstants * @see DESCipher */ final class DESedeCrypt extends DESCrypt implements DESConstants {     /*     * the expanded key used in encrypt/decrypt/encrypt phase     */    private byte[] key1 = null;    private byte[] key2 = null;    private byte[] key3 = null;    private byte[] buf1, buf2;     /*     * constructor     */    DESedeCrypt() {        buf1 = new byte[DES_BLOCK_SIZE];        buf2 = new byte[DES_BLOCK_SIZE];    }     void init(boolean decrypting, String algorithm, byte[] keys)            throws InvalidKeyException {        if (!algorithm.equalsIgnoreCase("DESede")                    && !algorithm.equalsIgnoreCase("TripleDES")) {            throw new InvalidKeyException                ("Wrong algorithm: DESede or TripleDES required");        }        if (keys.length != DES_BLOCK_SIZE * 3) {            throw new InvalidKeyException("Wrong key size");        }         byte[] keybuf = new byte[DES_BLOCK_SIZE];         // retrieve the first key        key1 = new byte[128];        System.arraycopy(keys, 0, keybuf, 0, DES_BLOCK_SIZE);        expandKey(keybuf);        System.arraycopy(expandedKey, 0, key1, 0, 128);         // check if the third key is the same        if (keyEquals(keybuf, 0, keys, DES_BLOCK_SIZE*2, DES_BLOCK_SIZE)) {            key3 = key1;        } else {            key3 = new byte[128];            System.arraycopy(keys, DES_BLOCK_SIZE*2, keybuf, 0,                             DES_BLOCK_SIZE);            expandKey(keybuf);            System.arraycopy(expandedKey, 0, key3, 0, 128);        }         // retrieve the second key        key2 = new byte[128];        System.arraycopy(keys, DES_BLOCK_SIZE, keybuf, 0, DES_BLOCK_SIZE);        expandKey(keybuf);        System.arraycopy(expandedKey, 0, key2, 0, 128);     }     /**     * Performs encryption operation.     *     * <p>The input plain text <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 buffer with the input data to be encrypted     * @param plainOffset the offset in <code>plain</code>     * @param cipher the buffer for the result     * @param cipherOffset the offset in <code>cipher</code>     */    void encryptBlock(byte[] plain, int plainOffset,                 byte[] cipher, int cipherOffset)    {        expandedKey = key1;        decrypting = false;        cipherBlock(plain, plainOffset, buf1, 0);         expandedKey = key2;        decrypting = true;        cipherBlock(buf1, 0, buf2, 0);         expandedKey = key3;        decrypting = false;        cipherBlock(buf2, 0, cipher, cipherOffset);    }     /**     * Performs decryption operation.     *     * <p>The input cipher text <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 buffer with the input data to be decrypted     * @param cipherOffset the offset in <code>cipherOffset</code>     * @param plain the buffer for the result     * @param plainOffset the offset in <code>plain</code>     */    void decryptBlock(byte[] cipher, int cipherOffset,                 byte[] plain, int plainOffset)    {        expandedKey = key3;        decrypting = true;        cipherBlock(cipher, cipherOffset, buf1, 0);         expandedKey = key2;        decrypting = false;        cipherBlock(buf1, 0, buf2, 0);         expandedKey = key1;        decrypting = true;        cipherBlock(buf2, 0, plain, plainOffset);    }     private boolean keyEquals(byte[] key1, int off1,                              byte[] key2, int off2, int len) {         for (int i=0; i<len; i++) {            if (key1[i+off1] != key2[i+off2])                return false;        }        return true;    }}