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; |
| 27 | |
| 28 | import java.util.*; |
| 29 | |
| 30 | import java.security.*; |
| 31 | import java.security.Provider.Service; |
| 32 | import java.security.spec.AlgorithmParameterSpec; |
| 33 | |
| 34 | import java.nio.ByteBuffer; |
| 35 | |
| 36 | import sun.security.util.Debug; |
| 37 | import sun.security.jca.*; |
| 38 | import sun.security.jca.GetInstance.Instance; |
| 39 | |
| 40 | /** |
| 41 | * This class provides the functionality of a "Message Authentication Code" |
| 42 | * (MAC) algorithm. |
| 43 | * |
| 44 | * <p> A MAC provides a way to check |
| 45 | * the integrity of information transmitted over or stored in an unreliable |
| 46 | * medium, based on a secret key. Typically, message |
| 47 | * authentication codes are used between two parties that share a secret |
| 48 | * key in order to validate information transmitted between these |
| 49 | * parties. |
| 50 | * |
| 51 | * <p> A MAC mechanism that is based on cryptographic hash functions is |
| 52 | * referred to as HMAC. HMAC can be used with any cryptographic hash function, |
| 53 | * e.g., MD5 or SHA-1, in combination with a secret shared key. HMAC is |
| 54 | * specified in RFC 2104. |
| 55 | * |
| 56 | * @author Jan Luehe |
| 57 | * |
| 58 | * @since 1.4 |
| 59 | */ |
| 60 | |
| 61 | public class Mac implements Cloneable { |
| 62 | |
| 63 | private static final Debug debug = |
| 64 | Debug.getInstance("jca", "Mac"); |
| 65 | |
| 66 | // The provider |
| 67 | private Provider provider; |
| 68 | |
| 69 | // The provider implementation (delegate) |
| 70 | private MacSpi spi; |
| 71 | |
| 72 | // The name of the MAC algorithm. |
| 73 | private final String algorithm; |
| 74 | |
| 75 | // Has this object been initialized? |
| 76 | private boolean initialized = false; |
| 77 | |
| 78 | // next service to try in provider selection |
| 79 | // null once provider is selected |
| 80 | private Service firstService; |
| 81 | |
| 82 | // remaining services to try in provider selection |
| 83 | // null once provider is selected |
| 84 | private Iterator serviceIterator; |
| 85 | |
| 86 | private final Object lock; |
| 87 | |
| 88 | /** |
| 89 | * Creates a MAC object. |
| 90 | * |
| 91 | * @param macSpi the delegate |
| 92 | * @param provider the provider |
| 93 | * @param algorithm the algorithm |
| 94 | */ |
| 95 | protected Mac(MacSpi macSpi, Provider provider, String algorithm) { |
| 96 | this.spi = macSpi; |
| 97 | this.provider = provider; |
| 98 | this.algorithm = algorithm; |
| 99 | serviceIterator = null; |
| 100 | lock = null; |
| 101 | } |
| 102 | |
| 103 | private Mac(Service s, Iterator t, String algorithm) { |
| 104 | firstService = s; |
| 105 | serviceIterator = t; |
| 106 | this.algorithm = algorithm; |
| 107 | lock = new Object(); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Returns the algorithm name of this <code>Mac</code> object. |
| 112 | * |
| 113 | * <p>This is the same name that was specified in one of the |
| 114 | * <code>getInstance</code> calls that created this |
| 115 | * <code>Mac</code> object. |
| 116 | * |
| 117 | * @return the algorithm name of this <code>Mac</code> object. |
| 118 | */ |
| 119 | public final String getAlgorithm() { |
| 120 | return this.algorithm; |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * Returns a <code>Mac</code> object that implements the |
| 125 | * specified MAC algorithm. |
| 126 | * |
| 127 | * <p> This method traverses the list of registered security Providers, |
| 128 | * starting with the most preferred Provider. |
| 129 | * A new Mac object encapsulating the |
| 130 | * MacSpi implementation from the first |
| 131 | * Provider that supports the specified algorithm is returned. |
| 132 | * |
| 133 | * <p> Note that the list of registered providers may be retrieved via |
| 134 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 135 | * |
| 136 | * @param algorithm the standard name of the requested MAC algorithm. |
| 137 | * See Appendix A in the <a href= |
| 138 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 139 | * Java Cryptography Architecture Reference Guide</a> |
| 140 | * for information about standard algorithm names. |
| 141 | * |
| 142 | * @return the new <code>Mac</code> object. |
| 143 | * |
| 144 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 145 | * MacSpi implementation for the |
| 146 | * specified algorithm. |
| 147 | * |
| 148 | * @see java.security.Provider |
| 149 | */ |
| 150 | public static final Mac getInstance(String algorithm) |
| 151 | throws NoSuchAlgorithmException { |
| 152 | List services = GetInstance.getServices("Mac", algorithm); |
| 153 | // make sure there is at least one service from a signed provider |
| 154 | Iterator t = services.iterator(); |
| 155 | while (t.hasNext()) { |
| 156 | Service s = (Service)t.next(); |
| 157 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 158 | continue; |
| 159 | } |
| 160 | return new Mac(s, t, algorithm); |
| 161 | } |
| 162 | throw new NoSuchAlgorithmException |
| 163 | ("Algorithm " + algorithm + " not available"); |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Returns a <code>Mac</code> object that implements the |
| 168 | * specified MAC algorithm. |
| 169 | * |
| 170 | * <p> A new Mac object encapsulating the |
| 171 | * MacSpi implementation from the specified provider |
| 172 | * is returned. The specified provider must be registered |
| 173 | * in the security provider list. |
| 174 | * |
| 175 | * <p> Note that the list of registered providers may be retrieved via |
| 176 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 177 | * |
| 178 | * @param algorithm the standard name of the requested MAC algorithm. |
| 179 | * See Appendix A in the <a href= |
| 180 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 181 | * Java Cryptography Architecture Reference Guide</a> |
| 182 | * for information about standard algorithm names. |
| 183 | * |
| 184 | * @param provider the name of the provider. |
| 185 | * |
| 186 | * @return the new <code>Mac</code> object. |
| 187 | * |
| 188 | * @exception NoSuchAlgorithmException if a MacSpi |
| 189 | * implementation for the specified algorithm is not |
| 190 | * available from the specified provider. |
| 191 | * |
| 192 | * @exception NoSuchProviderException if the specified provider is not |
| 193 | * registered in the security provider list. |
| 194 | * |
| 195 | * @exception IllegalArgumentException if the <code>provider</code> |
| 196 | * is null or empty. |
| 197 | * |
| 198 | * @see java.security.Provider |
| 199 | */ |
| 200 | public static final Mac getInstance(String algorithm, String provider) |
| 201 | throws NoSuchAlgorithmException, NoSuchProviderException { |
| 202 | Instance instance = JceSecurity.getInstance |
| 203 | ("Mac", MacSpi.class, algorithm, provider); |
| 204 | return new Mac((MacSpi)instance.impl, instance.provider, algorithm); |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Returns a <code>Mac</code> object that implements the |
| 209 | * specified MAC algorithm. |
| 210 | * |
| 211 | * <p> A new Mac object encapsulating the |
| 212 | * MacSpi implementation from the specified Provider |
| 213 | * object is returned. Note that the specified Provider object |
| 214 | * does not have to be registered in the provider list. |
| 215 | * |
| 216 | * @param algorithm the standard name of the requested MAC algorithm. |
| 217 | * See Appendix A in the <a href= |
| 218 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 219 | * Java Cryptography Architecture Reference Guide</a> |
| 220 | * for information about standard algorithm names. |
| 221 | * |
| 222 | * @param provider the provider. |
| 223 | * |
| 224 | * @return the new <code>Mac</code> object. |
| 225 | * |
| 226 | * @exception NoSuchAlgorithmException if a MacSpi |
| 227 | * implementation for the specified algorithm is not available |
| 228 | * from the specified Provider object. |
| 229 | * |
| 230 | * @exception IllegalArgumentException if the <code>provider</code> |
| 231 | * is null. |
| 232 | * |
| 233 | * @see java.security.Provider |
| 234 | */ |
| 235 | public static final Mac getInstance(String algorithm, Provider provider) |
| 236 | throws NoSuchAlgorithmException { |
| 237 | Instance instance = JceSecurity.getInstance |
| 238 | ("Mac", MacSpi.class, algorithm, provider); |
| 239 | return new Mac((MacSpi)instance.impl, instance.provider, algorithm); |
| 240 | } |
| 241 | |
| 242 | // max number of debug warnings to print from chooseFirstProvider() |
| 243 | private static int warnCount = 10; |
| 244 | |
| 245 | /** |
| 246 | * Choose the Spi from the first provider available. Used if |
| 247 | * delayed provider selection is not possible because init() |
| 248 | * is not the first method called. |
| 249 | */ |
| 250 | void chooseFirstProvider() { |
| 251 | if ((spi != null) || (serviceIterator == null)) { |
| 252 | return; |
| 253 | } |
| 254 | synchronized (lock) { |
| 255 | if (spi != null) { |
| 256 | return; |
| 257 | } |
| 258 | if (debug != null) { |
| 259 | int w = --warnCount; |
| 260 | if (w >= 0) { |
| 261 | debug.println("Mac.init() not first method " |
| 262 | + "called, disabling delayed provider selection"); |
| 263 | if (w == 0) { |
| 264 | debug.println("Further warnings of this type will " |
| 265 | + "be suppressed"); |
| 266 | } |
| 267 | new Exception("Call trace").printStackTrace(); |
| 268 | } |
| 269 | } |
| 270 | Exception lastException = null; |
| 271 | while ((firstService != null) || serviceIterator.hasNext()) { |
| 272 | Service s; |
| 273 | if (firstService != null) { |
| 274 | s = firstService; |
| 275 | firstService = null; |
| 276 | } else { |
| 277 | s = (Service)serviceIterator.next(); |
| 278 | } |
| 279 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 280 | continue; |
| 281 | } |
| 282 | try { |
| 283 | Object obj = s.newInstance(null); |
| 284 | if (obj instanceof MacSpi == false) { |
| 285 | continue; |
| 286 | } |
| 287 | spi = (MacSpi)obj; |
| 288 | provider = s.getProvider(); |
| 289 | // not needed any more |
| 290 | firstService = null; |
| 291 | serviceIterator = null; |
| 292 | return; |
| 293 | } catch (NoSuchAlgorithmException e) { |
| 294 | lastException = e; |
| 295 | } |
| 296 | } |
| 297 | ProviderException e = new ProviderException |
| 298 | ("Could not construct MacSpi instance"); |
| 299 | if (lastException != null) { |
| 300 | e.initCause(lastException); |
| 301 | } |
| 302 | throw e; |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | private void chooseProvider(Key key, AlgorithmParameterSpec params) |
| 307 | throws InvalidKeyException, InvalidAlgorithmParameterException { |
| 308 | synchronized (lock) { |
| 309 | if (spi != null) { |
| 310 | spi.engineInit(key, params); |
| 311 | return; |
| 312 | } |
| 313 | Exception lastException = null; |
| 314 | while ((firstService != null) || serviceIterator.hasNext()) { |
| 315 | Service s; |
| 316 | if (firstService != null) { |
| 317 | s = firstService; |
| 318 | firstService = null; |
| 319 | } else { |
| 320 | s = (Service)serviceIterator.next(); |
| 321 | } |
| 322 | // if provider says it does not support this key, ignore it |
| 323 | if (s.supportsParameter(key) == false) { |
| 324 | continue; |
| 325 | } |
| 326 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 327 | continue; |
| 328 | } |
| 329 | try { |
| 330 | MacSpi spi = (MacSpi)s.newInstance(null); |
| 331 | spi.engineInit(key, params); |
| 332 | provider = s.getProvider(); |
| 333 | this.spi = spi; |
| 334 | firstService = null; |
| 335 | serviceIterator = null; |
| 336 | return; |
| 337 | } catch (Exception e) { |
| 338 | // NoSuchAlgorithmException from newInstance() |
| 339 | // InvalidKeyException from init() |
| 340 | // RuntimeException (ProviderException) from init() |
| 341 | if (lastException == null) { |
| 342 | lastException = e; |
| 343 | } |
| 344 | } |
| 345 | } |
| 346 | // no working provider found, fail |
| 347 | if (lastException instanceof InvalidKeyException) { |
| 348 | throw (InvalidKeyException)lastException; |
| 349 | } |
| 350 | if (lastException instanceof InvalidAlgorithmParameterException) { |
| 351 | throw (InvalidAlgorithmParameterException)lastException; |
| 352 | } |
| 353 | if (lastException instanceof RuntimeException) { |
| 354 | throw (RuntimeException)lastException; |
| 355 | } |
| 356 | String kName = (key != null) ? key.getClass().getName() : "(null)"; |
| 357 | throw new InvalidKeyException |
| 358 | ("No installed provider supports this key: " |
| 359 | + kName, lastException); |
| 360 | } |
| 361 | } |
| 362 | |
| 363 | /** |
| 364 | * Returns the provider of this <code>Mac</code> object. |
| 365 | * |
| 366 | * @return the provider of this <code>Mac</code> object. |
| 367 | */ |
| 368 | public final Provider getProvider() { |
| 369 | chooseFirstProvider(); |
| 370 | return this.provider; |
| 371 | } |
| 372 | |
| 373 | /** |
| 374 | * Returns the length of the MAC in bytes. |
| 375 | * |
| 376 | * @return the MAC length in bytes. |
| 377 | */ |
| 378 | public final int getMacLength() { |
| 379 | chooseFirstProvider(); |
| 380 | return spi.engineGetMacLength(); |
| 381 | } |
| 382 | |
| 383 | /** |
| 384 | * Initializes this <code>Mac</code> object with the given key. |
| 385 | * |
| 386 | * @param key the key. |
| 387 | * |
| 388 | * @exception InvalidKeyException if the given key is inappropriate for |
| 389 | * initializing this MAC. |
| 390 | */ |
| 391 | public final void init(Key key) throws InvalidKeyException { |
| 392 | try { |
| 393 | if (spi != null) { |
| 394 | spi.engineInit(key, null); |
| 395 | } else { |
| 396 | chooseProvider(key, null); |
| 397 | } |
| 398 | } catch (InvalidAlgorithmParameterException e) { |
| 399 | throw new InvalidKeyException("init() failed", e); |
| 400 | } |
| 401 | initialized = true; |
| 402 | } |
| 403 | |
| 404 | /** |
| 405 | * Initializes this <code>Mac</code> object with the given key and |
| 406 | * algorithm parameters. |
| 407 | * |
| 408 | * @param key the key. |
| 409 | * @param params the algorithm parameters. |
| 410 | * |
| 411 | * @exception InvalidKeyException if the given key is inappropriate for |
| 412 | * initializing this MAC. |
| 413 | * @exception InvalidAlgorithmParameterException if the given algorithm |
| 414 | * parameters are inappropriate for this MAC. |
| 415 | */ |
| 416 | public final void init(Key key, AlgorithmParameterSpec params) |
| 417 | throws InvalidKeyException, InvalidAlgorithmParameterException { |
| 418 | if (spi != null) { |
| 419 | spi.engineInit(key, params); |
| 420 | } else { |
| 421 | chooseProvider(key, params); |
| 422 | } |
| 423 | initialized = true; |
| 424 | } |
| 425 | |
| 426 | /** |
| 427 | * Processes the given byte. |
| 428 | * |
| 429 | * @param input the input byte to be processed. |
| 430 | * |
| 431 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 432 | * initialized. |
| 433 | */ |
| 434 | public final void update(byte input) throws IllegalStateException { |
| 435 | chooseFirstProvider(); |
| 436 | if (initialized == false) { |
| 437 | throw new IllegalStateException("MAC not initialized"); |
| 438 | } |
| 439 | spi.engineUpdate(input); |
| 440 | } |
| 441 | |
| 442 | /** |
| 443 | * Processes the given array of bytes. |
| 444 | * |
| 445 | * @param input the array of bytes to be processed. |
| 446 | * |
| 447 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 448 | * initialized. |
| 449 | */ |
| 450 | public final void update(byte[] input) throws IllegalStateException { |
| 451 | chooseFirstProvider(); |
| 452 | if (initialized == false) { |
| 453 | throw new IllegalStateException("MAC not initialized"); |
| 454 | } |
| 455 | if (input != null) { |
| 456 | spi.engineUpdate(input, 0, input.length); |
| 457 | } |
| 458 | } |
| 459 | |
| 460 | /** |
| 461 | * Processes the first <code>len</code> bytes in <code>input</code>, |
| 462 | * starting at <code>offset</code> inclusive. |
| 463 | * |
| 464 | * @param input the input buffer. |
| 465 | * @param offset the offset in <code>input</code> where the input starts. |
| 466 | * @param len the number of bytes to process. |
| 467 | * |
| 468 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 469 | * initialized. |
| 470 | */ |
| 471 | public final void update(byte[] input, int offset, int len) |
| 472 | throws IllegalStateException { |
| 473 | chooseFirstProvider(); |
| 474 | if (initialized == false) { |
| 475 | throw new IllegalStateException("MAC not initialized"); |
| 476 | } |
| 477 | |
| 478 | if (input != null) { |
| 479 | if ((offset < 0) || (len > (input.length - offset)) || (len < 0)) |
| 480 | throw new IllegalArgumentException("Bad arguments"); |
| 481 | spi.engineUpdate(input, offset, len); |
| 482 | } |
| 483 | } |
| 484 | |
| 485 | /** |
| 486 | * Processes <code>input.remaining()</code> bytes in the ByteBuffer |
| 487 | * <code>input</code>, starting at <code>input.position()</code>. |
| 488 | * Upon return, the buffer's position will be equal to its limit; |
| 489 | * its limit will not have changed. |
| 490 | * |
| 491 | * @param input the ByteBuffer |
| 492 | * |
| 493 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 494 | * initialized. |
| 495 | * @since 1.5 |
| 496 | */ |
| 497 | public final void update(ByteBuffer input) { |
| 498 | chooseFirstProvider(); |
| 499 | if (initialized == false) { |
| 500 | throw new IllegalStateException("MAC not initialized"); |
| 501 | } |
| 502 | if (input == null) { |
| 503 | throw new IllegalArgumentException("Buffer must not be null"); |
| 504 | } |
| 505 | spi.engineUpdate(input); |
| 506 | } |
| 507 | |
| 508 | /** |
| 509 | * Finishes the MAC operation. |
| 510 | * |
| 511 | * <p>A call to this method resets this <code>Mac</code> object to the |
| 512 | * state it was in when previously initialized via a call to |
| 513 | * <code>init(Key)</code> or |
| 514 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 515 | * That is, the object is reset and available to generate another MAC from |
| 516 | * the same key, if desired, via new calls to <code>update</code> and |
| 517 | * <code>doFinal</code>. |
| 518 | * (In order to reuse this <code>Mac</code> object with a different key, |
| 519 | * it must be reinitialized via a call to <code>init(Key)</code> or |
| 520 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 521 | * |
| 522 | * @return the MAC result. |
| 523 | * |
| 524 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 525 | * initialized. |
| 526 | */ |
| 527 | public final byte[] doFinal() throws IllegalStateException { |
| 528 | chooseFirstProvider(); |
| 529 | if (initialized == false) { |
| 530 | throw new IllegalStateException("MAC not initialized"); |
| 531 | } |
| 532 | byte[] mac = spi.engineDoFinal(); |
| 533 | spi.engineReset(); |
| 534 | return mac; |
| 535 | } |
| 536 | |
| 537 | /** |
| 538 | * Finishes the MAC operation. |
| 539 | * |
| 540 | * <p>A call to this method resets this <code>Mac</code> object to the |
| 541 | * state it was in when previously initialized via a call to |
| 542 | * <code>init(Key)</code> or |
| 543 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 544 | * That is, the object is reset and available to generate another MAC from |
| 545 | * the same key, if desired, via new calls to <code>update</code> and |
| 546 | * <code>doFinal</code>. |
| 547 | * (In order to reuse this <code>Mac</code> object with a different key, |
| 548 | * it must be reinitialized via a call to <code>init(Key)</code> or |
| 549 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 550 | * |
| 551 | * <p>The MAC result is stored in <code>output</code>, starting at |
| 552 | * <code>outOffset</code> inclusive. |
| 553 | * |
| 554 | * @param output the buffer where the MAC result is stored |
| 555 | * @param outOffset the offset in <code>output</code> where the MAC is |
| 556 | * stored |
| 557 | * |
| 558 | * @exception ShortBufferException if the given output buffer is too small |
| 559 | * to hold the result |
| 560 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 561 | * initialized. |
| 562 | */ |
| 563 | public final void doFinal(byte[] output, int outOffset) |
| 564 | throws ShortBufferException, IllegalStateException |
| 565 | { |
| 566 | chooseFirstProvider(); |
| 567 | if (initialized == false) { |
| 568 | throw new IllegalStateException("MAC not initialized"); |
| 569 | } |
| 570 | int macLen = getMacLength(); |
| 571 | if (output == null || output.length-outOffset < macLen) { |
| 572 | throw new ShortBufferException |
| 573 | ("Cannot store MAC in output buffer"); |
| 574 | } |
| 575 | byte[] mac = doFinal(); |
| 576 | System.arraycopy(mac, 0, output, outOffset, macLen); |
| 577 | return; |
| 578 | } |
| 579 | |
| 580 | /** |
| 581 | * Processes the given array of bytes and finishes the MAC operation. |
| 582 | * |
| 583 | * <p>A call to this method resets this <code>Mac</code> object to the |
| 584 | * state it was in when previously initialized via a call to |
| 585 | * <code>init(Key)</code> or |
| 586 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 587 | * That is, the object is reset and available to generate another MAC from |
| 588 | * the same key, if desired, via new calls to <code>update</code> and |
| 589 | * <code>doFinal</code>. |
| 590 | * (In order to reuse this <code>Mac</code> object with a different key, |
| 591 | * it must be reinitialized via a call to <code>init(Key)</code> or |
| 592 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 593 | * |
| 594 | * @param input data in bytes |
| 595 | * @return the MAC result. |
| 596 | * |
| 597 | * @exception IllegalStateException if this <code>Mac</code> has not been |
| 598 | * initialized. |
| 599 | */ |
| 600 | public final byte[] doFinal(byte[] input) throws IllegalStateException |
| 601 | { |
| 602 | chooseFirstProvider(); |
| 603 | if (initialized == false) { |
| 604 | throw new IllegalStateException("MAC not initialized"); |
| 605 | } |
| 606 | update(input); |
| 607 | return doFinal(); |
| 608 | } |
| 609 | |
| 610 | /** |
| 611 | * Resets this <code>Mac</code> object. |
| 612 | * |
| 613 | * <p>A call to this method resets this <code>Mac</code> object to the |
| 614 | * state it was in when previously initialized via a call to |
| 615 | * <code>init(Key)</code> or |
| 616 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 617 | * That is, the object is reset and available to generate another MAC from |
| 618 | * the same key, if desired, via new calls to <code>update</code> and |
| 619 | * <code>doFinal</code>. |
| 620 | * (In order to reuse this <code>Mac</code> object with a different key, |
| 621 | * it must be reinitialized via a call to <code>init(Key)</code> or |
| 622 | * <code>init(Key, AlgorithmParameterSpec)</code>. |
| 623 | */ |
| 624 | public final void reset() { |
| 625 | chooseFirstProvider(); |
| 626 | spi.engineReset(); |
| 627 | } |
| 628 | |
| 629 | /** |
| 630 | * Returns a clone if the provider implementation is cloneable. |
| 631 | * |
| 632 | * @return a clone if the provider implementation is cloneable. |
| 633 | * |
| 634 | * @exception CloneNotSupportedException if this is called on a |
| 635 | * delegate that does not support <code>Cloneable</code>. |
| 636 | */ |
| 637 | public final Object clone() throws CloneNotSupportedException { |
| 638 | chooseFirstProvider(); |
| 639 | Mac that = (Mac)super.clone(); |
| 640 | that.spi = (MacSpi)this.spi.clone(); |
| 641 | return that; |
| 642 | } |
| 643 | } |