1/*
2 * Copyright (c) 1998, 2015, 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).
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17 * You should have received a copy of the GNU General Public License version
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24 */
25
26package javax.crypto.spec;
27
28import java.security.spec.AlgorithmParameterSpec;
29
30/**
31 * This class specifies the parameters used with the
32 * <a href="http://tools.ietf.org/html/rfc2040"><i>RC5</i></a>
33 * algorithm.
34 *
35 * <p> The parameters consist of a version number, a rounds count, a word
36 * size, and optionally an initialization vector (IV) (only in feedback mode).
37 *
38 * <p> This class can be used to initialize a {@code Cipher} object that
39 * implements the <i>RC5</i> algorithm as supplied by
40 * <a href="http://www.rsa.com">RSA Security LLC</a>,
41 * or any parties authorized by RSA Security.
42 *
43 * @author Jan Luehe
44 *
45 * @since 1.4
46 */
47public class RC5ParameterSpec implements AlgorithmParameterSpec {
48
49    private byte[] iv = null;
50    private int version;
51    private int rounds;
52    private int wordSize; // the word size in bits
53
54    /**
55     * Constructs a parameter set for RC5 from the given version, number of
56     * rounds and word size (in bits).
57     *
58     * @param version the version.
59     * @param rounds the number of rounds.
60     * @param wordSize the word size in bits.
61     */
62    public RC5ParameterSpec(int version, int rounds, int wordSize) {
63        this.version = version;
64        this.rounds = rounds;
65        this.wordSize = wordSize;
66    }
67
68    /**
69     * Constructs a parameter set for RC5 from the given version, number of
70     * rounds, word size (in bits), and IV.
71     *
72     * <p> Note that the size of the IV (block size) must be twice the word
73     * size. The bytes that constitute the IV are those between
74     * {@code iv[0]} and {@code iv[2*(wordSize/8)-1]} inclusive.
75     *
76     * @param version the version.
77     * @param rounds the number of rounds.
78     * @param wordSize the word size in bits.
79     * @param iv the buffer with the IV. The first {@code 2*(wordSize/8)}
80     * bytes of the buffer are copied to protect against subsequent
81     * modification.
82     * @exception IllegalArgumentException if {@code iv} is
83     * {@code null} or {@code (iv.length < 2 * (wordSize / 8))}
84     */
85    public RC5ParameterSpec(int version, int rounds, int wordSize, byte[] iv) {
86        this(version, rounds, wordSize, iv, 0);
87    }
88
89    /**
90     * Constructs a parameter set for RC5 from the given version, number of
91     * rounds, word size (in bits), and IV.
92     *
93     * <p> The IV is taken from {@code iv}, starting at
94     * {@code offset} inclusive.
95     * Note that the size of the IV (block size), starting at
96     * {@code offset} inclusive, must be twice the word size.
97     * The bytes that constitute the IV are those between
98     * {@code iv[offset]} and {@code iv[offset+2*(wordSize/8)-1]}
99     * inclusive.
100     *
101     * @param version the version.
102     * @param rounds the number of rounds.
103     * @param wordSize the word size in bits.
104     * @param iv the buffer with the IV. The first {@code 2*(wordSize/8)}
105     * bytes of the buffer beginning at {@code offset}
106     * inclusive are copied to protect against subsequent modification.
107     * @param offset the offset in {@code iv} where the IV starts.
108     * @exception IllegalArgumentException if {@code iv} is
109     * {@code null} or
110     * {@code (iv.length - offset < 2 * (wordSize / 8))}
111     */
112    public RC5ParameterSpec(int version, int rounds, int wordSize,
113                            byte[] iv, int offset) {
114        this.version = version;
115        this.rounds = rounds;
116        this.wordSize = wordSize;
117        if (iv == null) throw new IllegalArgumentException("IV missing");
118        int blockSize = (wordSize / 8) * 2;
119        if (iv.length - offset < blockSize) {
120            throw new IllegalArgumentException("IV too short");
121        }
122        this.iv = new byte[blockSize];
123        System.arraycopy(iv, offset, this.iv, 0, blockSize);
124    }
125
126    /**
127     * Returns the version.
128     *
129     * @return the version.
130     */
131    public int getVersion() {
132        return this.version;
133    }
134
135    /**
136     * Returns the number of rounds.
137     *
138     * @return the number of rounds.
139     */
140    public int getRounds() {
141        return this.rounds;
142    }
143
144    /**
145     * Returns the word size in bits.
146     *
147     * @return the word size in bits.
148     */
149    public int getWordSize() {
150        return this.wordSize;
151    }
152
153    /**
154     * Returns the IV or null if this parameter set does not contain an IV.
155     *
156     * @return the IV or null if this parameter set does not contain an IV.
157     * Returns a new array each time this method is called.
158     */
159    public byte[] getIV() {
160        return (iv == null? null:iv.clone());
161    }
162
163   /**
164     * Tests for equality between the specified object and this
165     * object. Two RC5ParameterSpec objects are considered equal if their
166     * version numbers, number of rounds, word sizes, and IVs are equal.
167     * (Two IV references are considered equal if both are {@code null}.)
168     *
169     * @param obj the object to test for equality with this object.
170     *
171     * @return true if the objects are considered equal, false if
172     * {@code obj} is null or otherwise.
173     */
174    public boolean equals(Object obj) {
175        if (obj == this) {
176            return true;
177        }
178        if (!(obj instanceof RC5ParameterSpec)) {
179            return false;
180        }
181        RC5ParameterSpec other = (RC5ParameterSpec) obj;
182
183        return ((version == other.version) &&
184                (rounds == other.rounds) &&
185                (wordSize == other.wordSize) &&
186                java.util.Arrays.equals(iv, other.iv));
187    }
188
189    /**
190     * Calculates a hash code value for the object.
191     * Objects that are equal will also have the same hashcode.
192     */
193    public int hashCode() {
194        int retval = 0;
195        if (iv != null) {
196            for (int i = 1; i < iv.length; i++) {
197                retval += iv[i] * i;
198            }
199        }
200        retval += (version + rounds + wordSize);
201        return retval;
202    }
203}
204