| 1 | /* BaseMode.java -- |
| 2 | Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is a part of GNU Classpath. |
| 5 | |
| 6 | GNU Classpath is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or (at |
| 9 | your option) any later version. |
| 10 | |
| 11 | GNU Classpath is distributed in the hope that it will be useful, but |
| 12 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GNU Classpath; if not, write to the Free Software |
| 18 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| 19 | USA |
| 20 | |
| 21 | Linking this library statically or dynamically with other modules is |
| 22 | making a combined work based on this library. Thus, the terms and |
| 23 | conditions of the GNU General Public License cover the whole |
| 24 | combination. |
| 25 | |
| 26 | As a special exception, the copyright holders of this library give you |
| 27 | permission to link this library with independent modules to produce an |
| 28 | executable, regardless of the license terms of these independent |
| 29 | modules, and to copy and distribute the resulting executable under |
| 30 | terms of your choice, provided that you also meet, for each linked |
| 31 | independent module, the terms and conditions of the license of that |
| 32 | module. An independent module is a module which is not derived from |
| 33 | or based on this library. If you modify this library, you may extend |
| 34 | this exception to your version of the library, but you are not |
| 35 | obligated to do so. If you do not wish to do so, delete this |
| 36 | exception statement from your version. */ |
| 37 | |
| 38 | |
| 39 | package gnu.javax.crypto.mode; |
| 40 | |
| 41 | import gnu.javax.crypto.cipher.IBlockCipher; |
| 42 | |
| 43 | import java.security.InvalidKeyException; |
| 44 | import java.util.ArrayList; |
| 45 | import java.util.Arrays; |
| 46 | import java.util.Collections; |
| 47 | import java.util.HashMap; |
| 48 | import java.util.Iterator; |
| 49 | import java.util.Map; |
| 50 | |
| 51 | /** |
| 52 | * A basic abstract class to facilitate implementing block cipher modes of |
| 53 | * operations. |
| 54 | */ |
| 55 | public abstract class BaseMode |
| 56 | implements IMode |
| 57 | { |
| 58 | /** The canonical name prefix of this mode. */ |
| 59 | protected String name; |
| 60 | /** The state indicator of this instance. */ |
| 61 | protected int state; |
| 62 | /** The underlying block cipher implementation. */ |
| 63 | protected IBlockCipher cipher; |
| 64 | /** The block size, in bytes, to operate the underlying block cipher in. */ |
| 65 | protected int cipherBlockSize; |
| 66 | /** The block size, in bytes, in which to operate the mode instance. */ |
| 67 | protected int modeBlockSize; |
| 68 | /** The initialisation vector value. */ |
| 69 | protected byte[] iv; |
| 70 | /** The instance lock. */ |
| 71 | protected Object lock = new Object(); |
| 72 | |
| 73 | /** |
| 74 | * Trivial constructor for use by concrete subclasses. |
| 75 | * |
| 76 | * @param name the canonical name prefix of this mode. |
| 77 | * @param underlyingCipher the implementation of the underlying cipher. |
| 78 | * @param cipherBlockSize the block size, in bytes, in which to operate the |
| 79 | * underlying cipher. |
| 80 | */ |
| 81 | protected BaseMode(String name, IBlockCipher underlyingCipher, |
| 82 | int cipherBlockSize) |
| 83 | { |
| 84 | super(); |
| 85 | |
| 86 | this.name = name; |
| 87 | this.cipher = underlyingCipher; |
| 88 | this.cipherBlockSize = cipherBlockSize; |
| 89 | state = -1; |
| 90 | } |
| 91 | |
| 92 | public void update(byte[] in, int inOffset, byte[] out, int outOffset) |
| 93 | throws IllegalStateException |
| 94 | { |
| 95 | synchronized (lock) |
| 96 | { |
| 97 | switch (state) |
| 98 | { |
| 99 | case ENCRYPTION: |
| 100 | encryptBlock(in, inOffset, out, outOffset); |
| 101 | break; |
| 102 | case DECRYPTION: |
| 103 | decryptBlock(in, inOffset, out, outOffset); |
| 104 | break; |
| 105 | default: |
| 106 | throw new IllegalStateException(); |
| 107 | } |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | public String name() |
| 112 | { |
| 113 | return new StringBuffer(name).append('(').append(cipher.name()).append(')') |
| 114 | .toString(); |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Returns the default value, in bytes, of the mode's block size. This value |
| 119 | * is part of the construction arguments passed to the Factory methods in |
| 120 | * {@link ModeFactory}. Unless changed by an invocation of any of the |
| 121 | * <code>init()</code> methods, a <i>Mode</i> instance would operate with |
| 122 | * the same block size as its underlying block cipher. As mentioned earlier, |
| 123 | * the block size of the underlying block cipher itself is specified in one of |
| 124 | * the method(s) available in the factory class. |
| 125 | * |
| 126 | * @return the default value, in bytes, of the mode's block size. |
| 127 | * @see ModeFactory |
| 128 | */ |
| 129 | public int defaultBlockSize() |
| 130 | { |
| 131 | return cipherBlockSize; |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Returns the default value, in bytes, of the underlying block cipher key |
| 136 | * size. |
| 137 | * |
| 138 | * @return the default value, in bytes, of the underlying cipher's key size. |
| 139 | */ |
| 140 | public int defaultKeySize() |
| 141 | { |
| 142 | return cipher.defaultKeySize(); |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Returns an {@link Iterator} over the supported block sizes. Each element |
| 147 | * returned by this object is an {@link Integer}. |
| 148 | * <p> |
| 149 | * The default behaviour is to return an iterator with just one value, which |
| 150 | * is that currently configured for the underlying block cipher. Concrete |
| 151 | * implementations may override this behaviour to signal their ability to |
| 152 | * support other values. |
| 153 | * |
| 154 | * @return an {@link Iterator} over the supported block sizes. |
| 155 | */ |
| 156 | public Iterator blockSizes() |
| 157 | { |
| 158 | ArrayList al = new ArrayList(); |
| 159 | al.add(Integer.valueOf(cipherBlockSize)); |
| 160 | return Collections.unmodifiableList(al).iterator(); |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Returns an {@link Iterator} over the supported underlying block cipher key |
| 165 | * sizes. Each element returned by this object is an instance of |
| 166 | * {@link Integer}. |
| 167 | * |
| 168 | * @return an {@link Iterator} over the supported key sizes. |
| 169 | */ |
| 170 | public Iterator keySizes() |
| 171 | { |
| 172 | return cipher.keySizes(); |
| 173 | } |
| 174 | |
| 175 | public void init(Map attributes) throws InvalidKeyException, |
| 176 | IllegalStateException |
| 177 | { |
| 178 | synchronized (lock) |
| 179 | { |
| 180 | if (state != -1) |
| 181 | throw new IllegalStateException(); |
| 182 | Integer want = (Integer) attributes.get(STATE); |
| 183 | if (want != null) |
| 184 | { |
| 185 | switch (want.intValue()) |
| 186 | { |
| 187 | case ENCRYPTION: |
| 188 | state = ENCRYPTION; |
| 189 | break; |
| 190 | case DECRYPTION: |
| 191 | state = DECRYPTION; |
| 192 | break; |
| 193 | default: |
| 194 | throw new IllegalArgumentException(); |
| 195 | } |
| 196 | } |
| 197 | Integer bs = (Integer) attributes.get(MODE_BLOCK_SIZE); |
| 198 | modeBlockSize = (bs == null ? cipherBlockSize : bs.intValue()); |
| 199 | byte[] iv = (byte[]) attributes.get(IV); |
| 200 | if (iv != null) |
| 201 | this.iv = (byte[]) iv.clone(); |
| 202 | else |
| 203 | this.iv = new byte[modeBlockSize]; |
| 204 | cipher.init(attributes); |
| 205 | setup(); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | public int currentBlockSize() |
| 210 | { |
| 211 | if (state == -1) |
| 212 | throw new IllegalStateException(); |
| 213 | return modeBlockSize; |
| 214 | } |
| 215 | |
| 216 | public void reset() |
| 217 | { |
| 218 | synchronized (lock) |
| 219 | { |
| 220 | state = -1; |
| 221 | iv = null; |
| 222 | cipher.reset(); |
| 223 | teardown(); |
| 224 | } |
| 225 | } |
| 226 | |
| 227 | public boolean selfTest() |
| 228 | { |
| 229 | int ks; |
| 230 | Iterator bit; |
| 231 | for (Iterator kit = keySizes(); kit.hasNext();) |
| 232 | { |
| 233 | ks = ((Integer) kit.next()).intValue(); |
| 234 | for (bit = blockSizes(); bit.hasNext();) |
| 235 | if (! testSymmetry(ks, ((Integer) bit.next()).intValue())) |
| 236 | return false; |
| 237 | } |
| 238 | return true; |
| 239 | } |
| 240 | |
| 241 | public abstract Object clone(); |
| 242 | |
| 243 | /** The initialisation phase of the concrete mode implementation. */ |
| 244 | public abstract void setup(); |
| 245 | |
| 246 | /** The termination phase of the concrete mode implementation. */ |
| 247 | public abstract void teardown(); |
| 248 | |
| 249 | public abstract void encryptBlock(byte[] in, int i, byte[] out, int o); |
| 250 | |
| 251 | public abstract void decryptBlock(byte[] in, int i, byte[] out, int o); |
| 252 | |
| 253 | private boolean testSymmetry(int ks, int bs) |
| 254 | { |
| 255 | try |
| 256 | { |
| 257 | IMode mode = (IMode) this.clone(); |
| 258 | byte[] iv = new byte[cipherBlockSize]; // all zeroes |
| 259 | byte[] k = new byte[ks]; |
| 260 | int i; |
| 261 | for (i = 0; i < ks; i++) |
| 262 | k[i] = (byte) i; |
| 263 | int blockCount = 5; |
| 264 | int limit = blockCount * bs; |
| 265 | byte[] pt = new byte[limit]; |
| 266 | for (i = 0; i < limit; i++) |
| 267 | pt[i] = (byte) i; |
| 268 | byte[] ct = new byte[limit]; |
| 269 | byte[] cpt = new byte[limit]; |
| 270 | Map map = new HashMap(); |
| 271 | map.put(KEY_MATERIAL, k); |
| 272 | map.put(CIPHER_BLOCK_SIZE, Integer.valueOf(cipherBlockSize)); |
| 273 | map.put(STATE, Integer.valueOf(ENCRYPTION)); |
| 274 | map.put(IV, iv); |
| 275 | map.put(MODE_BLOCK_SIZE, Integer.valueOf(bs)); |
| 276 | mode.reset(); |
| 277 | mode.init(map); |
| 278 | for (i = 0; i < blockCount; i++) |
| 279 | mode.update(pt, i * bs, ct, i * bs); |
| 280 | mode.reset(); |
| 281 | map.put(STATE, Integer.valueOf(DECRYPTION)); |
| 282 | mode.init(map); |
| 283 | for (i = 0; i < blockCount; i++) |
| 284 | mode.update(ct, i * bs, cpt, i * bs); |
| 285 | return Arrays.equals(pt, cpt); |
| 286 | } |
| 287 | catch (Exception x) |
| 288 | { |
| 289 | x.printStackTrace(System.err); |
| 290 | return false; |
| 291 | } |
| 292 | } |
| 293 | } |