J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2006 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 java.security; |
| 27 | |
| 28 | import java.util.*; |
| 29 | import java.lang.*; |
| 30 | import java.io.IOException; |
| 31 | import java.io.ByteArrayOutputStream; |
| 32 | import java.io.PrintStream; |
| 33 | import java.io.InputStream; |
| 34 | import java.io.ByteArrayInputStream; |
| 35 | |
| 36 | import java.nio.ByteBuffer; |
| 37 | |
| 38 | /** |
| 39 | * This MessageDigest class provides applications the functionality of a |
| 40 | * message digest algorithm, such as MD5 or SHA. |
| 41 | * Message digests are secure one-way hash functions that take arbitrary-sized |
| 42 | * data and output a fixed-length hash value. |
| 43 | * |
| 44 | * <p>A MessageDigest object starts out initialized. The data is |
| 45 | * processed through it using the {@link #update(byte) update} |
| 46 | * methods. At any point {@link #reset() reset} can be called |
| 47 | * to reset the digest. Once all the data to be updated has been |
| 48 | * updated, one of the {@link #digest() digest} methods should |
| 49 | * be called to complete the hash computation. |
| 50 | * |
| 51 | * <p>The <code>digest</code> method can be called once for a given number |
| 52 | * of updates. After <code>digest</code> has been called, the MessageDigest |
| 53 | * object is reset to its initialized state. |
| 54 | * |
| 55 | * <p>Implementations are free to implement the Cloneable interface. |
| 56 | * Client applications can test cloneability by attempting cloning |
| 57 | * and catching the CloneNotSupportedException: <p> |
| 58 | * |
| 59 | * <pre> |
| 60 | * MessageDigest md = MessageDigest.getInstance("SHA"); |
| 61 | * |
| 62 | * try { |
| 63 | * md.update(toChapter1); |
| 64 | * MessageDigest tc1 = md.clone(); |
| 65 | * byte[] toChapter1Digest = tc1.digest(); |
| 66 | * md.update(toChapter2); |
| 67 | * ...etc. |
| 68 | * } catch (CloneNotSupportedException cnse) { |
| 69 | * throw new DigestException("couldn't make digest of partial content"); |
| 70 | * } |
| 71 | * </pre> |
| 72 | * |
| 73 | * <p>Note that if a given implementation is not cloneable, it is |
| 74 | * still possible to compute intermediate digests by instantiating |
| 75 | * several instances, if the number of digests is known in advance. |
| 76 | * |
| 77 | * <p>Note that this class is abstract and extends from |
| 78 | * <code>MessageDigestSpi</code> for historical reasons. |
| 79 | * Application developers should only take notice of the methods defined in |
| 80 | * this <code>MessageDigest</code> class; all the methods in |
| 81 | * the superclass are intended for cryptographic service providers who wish to |
| 82 | * supply their own implementations of message digest algorithms. |
| 83 | * |
| 84 | * @author Benjamin Renaud |
| 85 | * |
| 86 | * |
| 87 | * @see DigestInputStream |
| 88 | * @see DigestOutputStream |
| 89 | */ |
| 90 | |
| 91 | public abstract class MessageDigest extends MessageDigestSpi { |
| 92 | |
| 93 | private String algorithm; |
| 94 | |
| 95 | // The state of this digest |
| 96 | private static final int INITIAL = 0; |
| 97 | private static final int IN_PROGRESS = 1; |
| 98 | private int state = INITIAL; |
| 99 | |
| 100 | // The provider |
| 101 | private Provider provider; |
| 102 | |
| 103 | /** |
| 104 | * Creates a message digest with the specified algorithm name. |
| 105 | * |
| 106 | * @param algorithm the standard name of the digest algorithm. |
| 107 | * See Appendix A in the <a href= |
| 108 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 109 | * Java Cryptography Architecture API Specification & Reference </a> |
| 110 | * for information about standard algorithm names. |
| 111 | */ |
| 112 | protected MessageDigest(String algorithm) { |
| 113 | this.algorithm = algorithm; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Returns a MessageDigest object that implements the specified digest |
| 118 | * algorithm. |
| 119 | * |
| 120 | * <p> This method traverses the list of registered security Providers, |
| 121 | * starting with the most preferred Provider. |
| 122 | * A new MessageDigest object encapsulating the |
| 123 | * MessageDigestSpi implementation from the first |
| 124 | * Provider that supports the specified algorithm is returned. |
| 125 | * |
| 126 | * <p> Note that the list of registered providers may be retrieved via |
| 127 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 128 | * |
| 129 | * @param algorithm the name of the algorithm requested. |
| 130 | * See Appendix A in the <a href= |
| 131 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 132 | * Java Cryptography Architecture API Specification & Reference </a> |
| 133 | * for information about standard algorithm names. |
| 134 | * |
| 135 | * @return a Message Digest object that implements the specified algorithm. |
| 136 | * |
| 137 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 138 | * MessageDigestSpi implementation for the |
| 139 | * specified algorithm. |
| 140 | * |
| 141 | * @see Provider |
| 142 | */ |
| 143 | public static MessageDigest getInstance(String algorithm) |
| 144 | throws NoSuchAlgorithmException { |
| 145 | try { |
| 146 | Object[] objs = Security.getImpl(algorithm, "MessageDigest", |
| 147 | (String)null); |
| 148 | if (objs[0] instanceof MessageDigest) { |
| 149 | MessageDigest md = (MessageDigest)objs[0]; |
| 150 | md.provider = (Provider)objs[1]; |
| 151 | return md; |
| 152 | } else { |
| 153 | MessageDigest delegate = |
| 154 | new Delegate((MessageDigestSpi)objs[0], algorithm); |
| 155 | delegate.provider = (Provider)objs[1]; |
| 156 | return delegate; |
| 157 | } |
| 158 | } catch(NoSuchProviderException e) { |
| 159 | throw new NoSuchAlgorithmException(algorithm + " not found"); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Returns a MessageDigest object that implements the specified digest |
| 165 | * algorithm. |
| 166 | * |
| 167 | * <p> A new MessageDigest object encapsulating the |
| 168 | * MessageDigestSpi implementation from the specified provider |
| 169 | * is returned. The specified provider must be registered |
| 170 | * in the security provider list. |
| 171 | * |
| 172 | * <p> Note that the list of registered providers may be retrieved via |
| 173 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 174 | * |
| 175 | * @param algorithm the name of the algorithm requested. |
| 176 | * See Appendix A in the <a href= |
| 177 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 178 | * Java Cryptography Architecture API Specification & Reference </a> |
| 179 | * for information about standard algorithm names. |
| 180 | * |
| 181 | * @param provider the name of the provider. |
| 182 | * |
| 183 | * @return a MessageDigest object that implements the specified algorithm. |
| 184 | * |
| 185 | * @exception NoSuchAlgorithmException if a MessageDigestSpi |
| 186 | * implementation for the specified algorithm is not |
| 187 | * available from the specified provider. |
| 188 | * |
| 189 | * @exception NoSuchProviderException if the specified provider is not |
| 190 | * registered in the security provider list. |
| 191 | * |
| 192 | * @exception IllegalArgumentException if the provider name is null |
| 193 | * or empty. |
| 194 | * |
| 195 | * @see Provider |
| 196 | */ |
| 197 | public static MessageDigest getInstance(String algorithm, String provider) |
| 198 | throws NoSuchAlgorithmException, NoSuchProviderException |
| 199 | { |
| 200 | if (provider == null || provider.length() == 0) |
| 201 | throw new IllegalArgumentException("missing provider"); |
| 202 | Object[] objs = Security.getImpl(algorithm, "MessageDigest", provider); |
| 203 | if (objs[0] instanceof MessageDigest) { |
| 204 | MessageDigest md = (MessageDigest)objs[0]; |
| 205 | md.provider = (Provider)objs[1]; |
| 206 | return md; |
| 207 | } else { |
| 208 | MessageDigest delegate = |
| 209 | new Delegate((MessageDigestSpi)objs[0], algorithm); |
| 210 | delegate.provider = (Provider)objs[1]; |
| 211 | return delegate; |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * Returns a MessageDigest object that implements the specified digest |
| 217 | * algorithm. |
| 218 | * |
| 219 | * <p> A new MessageDigest object encapsulating the |
| 220 | * MessageDigestSpi implementation from the specified Provider |
| 221 | * object is returned. Note that the specified Provider object |
| 222 | * does not have to be registered in the provider list. |
| 223 | * |
| 224 | * @param algorithm the name of the algorithm requested. |
| 225 | * See Appendix A in the <a href= |
| 226 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 227 | * Java Cryptography Architecture API Specification & Reference </a> |
| 228 | * for information about standard algorithm names. |
| 229 | * |
| 230 | * @param provider the provider. |
| 231 | * |
| 232 | * @return a MessageDigest object that implements the specified algorithm. |
| 233 | * |
| 234 | * @exception NoSuchAlgorithmException if a MessageDigestSpi |
| 235 | * implementation for the specified algorithm is not available |
| 236 | * from the specified Provider object. |
| 237 | * |
| 238 | * @exception IllegalArgumentException if the specified provider is null. |
| 239 | * |
| 240 | * @see Provider |
| 241 | * |
| 242 | * @since 1.4 |
| 243 | */ |
| 244 | public static MessageDigest getInstance(String algorithm, |
| 245 | Provider provider) |
| 246 | throws NoSuchAlgorithmException |
| 247 | { |
| 248 | if (provider == null) |
| 249 | throw new IllegalArgumentException("missing provider"); |
| 250 | Object[] objs = Security.getImpl(algorithm, "MessageDigest", provider); |
| 251 | if (objs[0] instanceof MessageDigest) { |
| 252 | MessageDigest md = (MessageDigest)objs[0]; |
| 253 | md.provider = (Provider)objs[1]; |
| 254 | return md; |
| 255 | } else { |
| 256 | MessageDigest delegate = |
| 257 | new Delegate((MessageDigestSpi)objs[0], algorithm); |
| 258 | delegate.provider = (Provider)objs[1]; |
| 259 | return delegate; |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * Returns the provider of this message digest object. |
| 265 | * |
| 266 | * @return the provider of this message digest object |
| 267 | */ |
| 268 | public final Provider getProvider() { |
| 269 | return this.provider; |
| 270 | } |
| 271 | |
| 272 | /** |
| 273 | * Updates the digest using the specified byte. |
| 274 | * |
| 275 | * @param input the byte with which to update the digest. |
| 276 | */ |
| 277 | public void update(byte input) { |
| 278 | engineUpdate(input); |
| 279 | state = IN_PROGRESS; |
| 280 | } |
| 281 | |
| 282 | /** |
| 283 | * Updates the digest using the specified array of bytes, starting |
| 284 | * at the specified offset. |
| 285 | * |
| 286 | * @param input the array of bytes. |
| 287 | * |
| 288 | * @param offset the offset to start from in the array of bytes. |
| 289 | * |
| 290 | * @param len the number of bytes to use, starting at |
| 291 | * <code>offset</code>. |
| 292 | */ |
| 293 | public void update(byte[] input, int offset, int len) { |
| 294 | if (input == null) { |
| 295 | throw new IllegalArgumentException("No input buffer given"); |
| 296 | } |
| 297 | if (input.length - offset < len) { |
| 298 | throw new IllegalArgumentException("Input buffer too short"); |
| 299 | } |
| 300 | engineUpdate(input, offset, len); |
| 301 | state = IN_PROGRESS; |
| 302 | } |
| 303 | |
| 304 | /** |
| 305 | * Updates the digest using the specified array of bytes. |
| 306 | * |
| 307 | * @param input the array of bytes. |
| 308 | */ |
| 309 | public void update(byte[] input) { |
| 310 | engineUpdate(input, 0, input.length); |
| 311 | state = IN_PROGRESS; |
| 312 | } |
| 313 | |
| 314 | /** |
| 315 | * Update the digest using the specified ByteBuffer. The digest is |
| 316 | * updated using the <code>input.remaining()</code> bytes starting |
| 317 | * at <code>input.position()</code>. |
| 318 | * Upon return, the buffer's position will be equal to its limit; |
| 319 | * its limit will not have changed. |
| 320 | * |
| 321 | * @param input the ByteBuffer |
| 322 | * @since 1.5 |
| 323 | */ |
| 324 | public final void update(ByteBuffer input) { |
| 325 | if (input == null) { |
| 326 | throw new NullPointerException(); |
| 327 | } |
| 328 | engineUpdate(input); |
| 329 | state = IN_PROGRESS; |
| 330 | } |
| 331 | |
| 332 | /** |
| 333 | * Completes the hash computation by performing final operations |
| 334 | * such as padding. The digest is reset after this call is made. |
| 335 | * |
| 336 | * @return the array of bytes for the resulting hash value. |
| 337 | */ |
| 338 | public byte[] digest() { |
| 339 | /* Resetting is the responsibility of implementors. */ |
| 340 | byte[] result = engineDigest(); |
| 341 | state = INITIAL; |
| 342 | return result; |
| 343 | } |
| 344 | |
| 345 | /** |
| 346 | * Completes the hash computation by performing final operations |
| 347 | * such as padding. The digest is reset after this call is made. |
| 348 | * |
| 349 | * @param buf output buffer for the computed digest |
| 350 | * |
| 351 | * @param offset offset into the output buffer to begin storing the digest |
| 352 | * |
| 353 | * @param len number of bytes within buf allotted for the digest |
| 354 | * |
| 355 | * @return the number of bytes placed into <code>buf</code> |
| 356 | * |
| 357 | * @exception DigestException if an error occurs. |
| 358 | */ |
| 359 | public int digest(byte[] buf, int offset, int len) throws DigestException { |
| 360 | if (buf == null) { |
| 361 | throw new IllegalArgumentException("No output buffer given"); |
| 362 | } |
| 363 | if (buf.length - offset < len) { |
| 364 | throw new IllegalArgumentException |
| 365 | ("Output buffer too small for specified offset and length"); |
| 366 | } |
| 367 | int numBytes = engineDigest(buf, offset, len); |
| 368 | state = INITIAL; |
| 369 | return numBytes; |
| 370 | } |
| 371 | |
| 372 | /** |
| 373 | * Performs a final update on the digest using the specified array |
| 374 | * of bytes, then completes the digest computation. That is, this |
| 375 | * method first calls {@link #update(byte[]) update(input)}, |
| 376 | * passing the <i>input</i> array to the <code>update</code> method, |
| 377 | * then calls {@link #digest() digest()}. |
| 378 | * |
| 379 | * @param input the input to be updated before the digest is |
| 380 | * completed. |
| 381 | * |
| 382 | * @return the array of bytes for the resulting hash value. |
| 383 | */ |
| 384 | public byte[] digest(byte[] input) { |
| 385 | update(input); |
| 386 | return digest(); |
| 387 | } |
| 388 | |
| 389 | /** |
| 390 | * Returns a string representation of this message digest object. |
| 391 | */ |
| 392 | public String toString() { |
| 393 | ByteArrayOutputStream baos = new ByteArrayOutputStream(); |
| 394 | PrintStream p = new PrintStream(baos); |
| 395 | p.print(algorithm+" Message Digest from "+provider.getName()+", "); |
| 396 | switch (state) { |
| 397 | case INITIAL: |
| 398 | p.print("<initialized>"); |
| 399 | break; |
| 400 | case IN_PROGRESS: |
| 401 | p.print("<in progress>"); |
| 402 | break; |
| 403 | } |
| 404 | p.println(); |
| 405 | return (baos.toString()); |
| 406 | } |
| 407 | |
| 408 | /** |
| 409 | * Compares two digests for equality. Does a simple byte compare. |
| 410 | * |
| 411 | * @param digesta one of the digests to compare. |
| 412 | * |
| 413 | * @param digestb the other digest to compare. |
| 414 | * |
| 415 | * @return true if the digests are equal, false otherwise. |
| 416 | */ |
| 417 | public static boolean isEqual(byte digesta[], byte digestb[]) { |
| 418 | if (digesta.length != digestb.length) |
| 419 | return false; |
| 420 | |
| 421 | for (int i = 0; i < digesta.length; i++) { |
| 422 | if (digesta[i] != digestb[i]) { |
| 423 | return false; |
| 424 | } |
| 425 | } |
| 426 | return true; |
| 427 | } |
| 428 | |
| 429 | /** |
| 430 | * Resets the digest for further use. |
| 431 | */ |
| 432 | public void reset() { |
| 433 | engineReset(); |
| 434 | state = INITIAL; |
| 435 | } |
| 436 | |
| 437 | /** |
| 438 | * Returns a string that identifies the algorithm, independent of |
| 439 | * implementation details. The name should be a standard |
| 440 | * Java Security name (such as "SHA", "MD5", and so on). |
| 441 | * See Appendix A in the <a href= |
| 442 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 443 | * Java Cryptography Architecture API Specification & Reference </a> |
| 444 | * for information about standard algorithm names. |
| 445 | * |
| 446 | * @return the name of the algorithm |
| 447 | */ |
| 448 | public final String getAlgorithm() { |
| 449 | return this.algorithm; |
| 450 | } |
| 451 | |
| 452 | /** |
| 453 | * Returns the length of the digest in bytes, or 0 if this operation is |
| 454 | * not supported by the provider and the implementation is not cloneable. |
| 455 | * |
| 456 | * @return the digest length in bytes, or 0 if this operation is not |
| 457 | * supported by the provider and the implementation is not cloneable. |
| 458 | * |
| 459 | * @since 1.2 |
| 460 | */ |
| 461 | public final int getDigestLength() { |
| 462 | int digestLen = engineGetDigestLength(); |
| 463 | if (digestLen == 0) { |
| 464 | try { |
| 465 | MessageDigest md = (MessageDigest)clone(); |
| 466 | byte[] digest = md.digest(); |
| 467 | return digest.length; |
| 468 | } catch (CloneNotSupportedException e) { |
| 469 | return digestLen; |
| 470 | } |
| 471 | } |
| 472 | return digestLen; |
| 473 | } |
| 474 | |
| 475 | /** |
| 476 | * Returns a clone if the implementation is cloneable. |
| 477 | * |
| 478 | * @return a clone if the implementation is cloneable. |
| 479 | * |
| 480 | * @exception CloneNotSupportedException if this is called on an |
| 481 | * implementation that does not support <code>Cloneable</code>. |
| 482 | */ |
| 483 | public Object clone() throws CloneNotSupportedException { |
| 484 | if (this instanceof Cloneable) { |
| 485 | return super.clone(); |
| 486 | } else { |
| 487 | throw new CloneNotSupportedException(); |
| 488 | } |
| 489 | } |
| 490 | |
| 491 | |
| 492 | |
| 493 | |
| 494 | /* |
| 495 | * The following class allows providers to extend from MessageDigestSpi |
| 496 | * rather than from MessageDigest. It represents a MessageDigest with an |
| 497 | * encapsulated, provider-supplied SPI object (of type MessageDigestSpi). |
| 498 | * If the provider implementation is an instance of MessageDigestSpi, |
| 499 | * the getInstance() methods above return an instance of this class, with |
| 500 | * the SPI object encapsulated. |
| 501 | * |
| 502 | * Note: All SPI methods from the original MessageDigest class have been |
| 503 | * moved up the hierarchy into a new class (MessageDigestSpi), which has |
| 504 | * been interposed in the hierarchy between the API (MessageDigest) |
| 505 | * and its original parent (Object). |
| 506 | */ |
| 507 | |
| 508 | static class Delegate extends MessageDigest { |
| 509 | |
| 510 | // The provider implementation (delegate) |
| 511 | private MessageDigestSpi digestSpi; |
| 512 | |
| 513 | // constructor |
| 514 | public Delegate(MessageDigestSpi digestSpi, String algorithm) { |
| 515 | super(algorithm); |
| 516 | this.digestSpi = digestSpi; |
| 517 | } |
| 518 | |
| 519 | /** |
| 520 | * Returns a clone if the delegate is cloneable. |
| 521 | * |
| 522 | * @return a clone if the delegate is cloneable. |
| 523 | * |
| 524 | * @exception CloneNotSupportedException if this is called on a |
| 525 | * delegate that does not support <code>Cloneable</code>. |
| 526 | */ |
| 527 | public Object clone() throws CloneNotSupportedException { |
| 528 | if (digestSpi instanceof Cloneable) { |
| 529 | MessageDigestSpi digestSpiClone = |
| 530 | (MessageDigestSpi)digestSpi.clone(); |
| 531 | // Because 'algorithm', 'provider', and 'state' are private |
| 532 | // members of our supertype, we must perform a cast to |
| 533 | // access them. |
| 534 | MessageDigest that = |
| 535 | new Delegate(digestSpiClone, |
| 536 | ((MessageDigest)this).algorithm); |
| 537 | that.provider = ((MessageDigest)this).provider; |
| 538 | that.state = ((MessageDigest)this).state; |
| 539 | return that; |
| 540 | } else { |
| 541 | throw new CloneNotSupportedException(); |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | protected int engineGetDigestLength() { |
| 546 | return digestSpi.engineGetDigestLength(); |
| 547 | } |
| 548 | |
| 549 | protected void engineUpdate(byte input) { |
| 550 | digestSpi.engineUpdate(input); |
| 551 | } |
| 552 | |
| 553 | protected void engineUpdate(byte[] input, int offset, int len) { |
| 554 | digestSpi.engineUpdate(input, offset, len); |
| 555 | } |
| 556 | |
| 557 | protected void engineUpdate(ByteBuffer input) { |
| 558 | digestSpi.engineUpdate(input); |
| 559 | } |
| 560 | |
| 561 | protected byte[] engineDigest() { |
| 562 | return digestSpi.engineDigest(); |
| 563 | } |
| 564 | |
| 565 | protected int engineDigest(byte[] buf, int offset, int len) |
| 566 | throws DigestException { |
| 567 | return digestSpi.engineDigest(buf, offset, len); |
| 568 | } |
| 569 | |
| 570 | protected void engineReset() { |
| 571 | digestSpi.engineReset(); |
| 572 | } |
| 573 | } |
| 574 | } |