J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1998-2007 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.crypto.spec; |
| 27 | |
| 28 | import java.security.spec.AlgorithmParameterSpec; |
| 29 | |
| 30 | /** |
| 31 | * This class specifies the parameters used with the |
| 32 | * <a href="http://www.ietf.org/rfc/rfc2040.txt"><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</code> object that |
| 39 | * implements the <i>RC5</i> algorithm as supplied by |
| 40 | * <a href="http://www.rsasecurity.com">RSA Security Inc.</a>, |
| 41 | * or any parties authorized by RSA Security. |
| 42 | * |
| 43 | * @author Jan Luehe |
| 44 | * |
| 45 | * @since 1.4 |
| 46 | */ |
| 47 | public 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]</code> and <code>iv[2*(wordSize/8)-1]</code> 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 | * </code> bytes of the buffer are copied to protect against subsequent |
| 81 | * modification. |
| 82 | * @exception IllegalArgumentException if <code>iv</code> is |
| 83 | * <code>null</code> or <code>(iv.length < 2 * (wordSize / 8))</code> |
| 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</code>, starting at |
| 94 | * <code>offset</code> inclusive. |
| 95 | * Note that the size of the IV (block size), starting at |
| 96 | * <code>offset</code> inclusive, must be twice the word size. |
| 97 | * The bytes that constitute the IV are those between |
| 98 | * <code>iv[offset]</code> and <code>iv[offset+2*(wordSize/8)-1]</code> |
| 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 | * </code> bytes of the buffer beginning at <code>offset</code> |
| 106 | * inclusive are copied to protect against subsequent modification. |
| 107 | * @param offset the offset in <code>iv</code> where the IV starts. |
| 108 | * @exception IllegalArgumentException if <code>iv</code> is |
| 109 | * <code>null</code> or |
| 110 | * <code>(iv.length - offset < 2 * (wordSize / 8))</code> |
| 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:(byte[])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 <tt>null</tt>.) |
| 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</code> 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 | } |