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
26package com.sun.crypto.provider;
27
28import 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 */
45abstract 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}
103