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| 1 | +/* | |
| 2 | + * Copyright (c) 1997, 2011, 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). | |
| 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * 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.*; | |
| 33 | + | |
| 34 | +import sun.security.util.Debug; | |
| 35 | +import sun.security.jca.*; | |
| 36 | +import sun.security.jca.GetInstance.Instance; | |
| 37 | + | |
| 38 | +/** | |
| 39 | + * This class provides the functionality of a key agreement (or key | |
| 40 | + * exchange) protocol. | |
| 41 | + * <p> | |
| 42 | + * The keys involved in establishing a shared secret are created by one of the | |
| 43 | + * key generators (<code>KeyPairGenerator</code> or | |
| 44 | + * <code>KeyGenerator</code>), a <code>KeyFactory</code>, or as a result from | |
| 45 | + * an intermediate phase of the key agreement protocol. | |
| 46 | + * | |
| 47 | + * <p> For each of the correspondents in the key exchange, <code>doPhase</code> | |
| 48 | + * needs to be called. For example, if this key exchange is with one other | |
| 49 | + * party, <code>doPhase</code> needs to be called once, with the | |
| 50 | + * <code>lastPhase</code> flag set to <code>true</code>. | |
| 51 | + * If this key exchange is | |
| 52 | + * with two other parties, <code>doPhase</code> needs to be called twice, | |
| 53 | + * the first time setting the <code>lastPhase</code> flag to | |
| 54 | + * <code>false</code>, and the second time setting it to <code>true</code>. | |
| 55 | + * There may be any number of parties involved in a key exchange. | |
| 56 | + * | |
| 57 | + * <p> Every implementation of the Java platform is required to support the | |
| 58 | + * following standard <code>KeyAgreement</code> algorithm: | |
| 59 | + * <ul> | |
| 60 | + * <li><tt>DiffieHellman</tt></li> | |
| 61 | + * </ul> | |
| 62 | + * This algorithm is described in the <a href= | |
| 63 | + * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> | |
| 64 | + * KeyAgreement section</a> of the | |
| 65 | + * Java Cryptography Architecture Standard Algorithm Name Documentation. | |
| 66 | + * Consult the release documentation for your implementation to see if any | |
| 67 | + * other algorithms are supported. | |
| 68 | + * | |
| 69 | + * @author Jan Luehe | |
| 70 | + * | |
| 71 | + * @see KeyGenerator | |
| 72 | + * @see SecretKey | |
| 73 | + * @since 1.4 | |
| 74 | + */ | |
| 75 | + | |
| 76 | +public class KeyAgreement { | |
| 77 | + | |
| 78 | + private static final Debug debug = | |
| 79 | + Debug.getInstance("jca", "KeyAgreement"); | |
| 80 | + | |
| 81 | + // The provider | |
| 82 | + private Provider provider; | |
| 83 | + | |
| 84 | + // The provider implementation (delegate) | |
| 85 | + private KeyAgreementSpi spi; | |
| 86 | + | |
| 87 | + // The name of the key agreement algorithm. | |
| 88 | + private final String algorithm; | |
| 89 | + | |
| 90 | + // next service to try in provider selection | |
| 91 | + // null once provider is selected | |
| 92 | + private Service firstService; | |
| 93 | + | |
| 94 | + // remaining services to try in provider selection | |
| 95 | + // null once provider is selected | |
| 96 | + private Iterator serviceIterator; | |
| 97 | + | |
| 98 | + private final Object lock; | |
| 99 | + | |
| 100 | + /** | |
| 101 | + * Creates a KeyAgreement object. | |
| 102 | + * | |
| 103 | + * @param keyAgreeSpi the delegate | |
| 104 | + * @param provider the provider | |
| 105 | + * @param algorithm the algorithm | |
| 106 | + */ | |
| 107 | + protected KeyAgreement(KeyAgreementSpi keyAgreeSpi, Provider provider, | |
| 108 | + String algorithm) { | |
| 109 | + this.spi = keyAgreeSpi; | |
| 110 | + this.provider = provider; | |
| 111 | + this.algorithm = algorithm; | |
| 112 | + lock = null; | |
| 113 | + } | |
| 114 | + | |
| 115 | + private KeyAgreement(Service s, Iterator t, String algorithm) { | |
| 116 | + firstService = s; | |
| 117 | + serviceIterator = t; | |
| 118 | + this.algorithm = algorithm; | |
| 119 | + lock = new Object(); | |
| 120 | + } | |
| 121 | + | |
| 122 | + /** | |
| 123 | + * Returns the algorithm name of this <code>KeyAgreement</code> object. | |
| 124 | + * | |
| 125 | + * <p>This is the same name that was specified in one of the | |
| 126 | + * <code>getInstance</code> calls that created this | |
| 127 | + * <code>KeyAgreement</code> object. | |
| 128 | + * | |
| 129 | + * @return the algorithm name of this <code>KeyAgreement</code> object. | |
| 130 | + */ | |
| 131 | + public final String getAlgorithm() { | |
| 132 | + return this.algorithm; | |
| 133 | + } | |
| 134 | + | |
| 135 | + /** | |
| 136 | + * Returns a <code>KeyAgreement</code> object that implements the | |
| 137 | + * specified key agreement algorithm. | |
| 138 | + * | |
| 139 | + * <p> This method traverses the list of registered security Providers, | |
| 140 | + * starting with the most preferred Provider. | |
| 141 | + * A new KeyAgreement object encapsulating the | |
| 142 | + * KeyAgreementSpi implementation from the first | |
| 143 | + * Provider that supports the specified algorithm is returned. | |
| 144 | + * | |
| 145 | + * <p> Note that the list of registered providers may be retrieved via | |
| 146 | + * the {@link Security#getProviders() Security.getProviders()} method. | |
| 147 | + * | |
| 148 | + * @param algorithm the standard name of the requested key agreement | |
| 149 | + * algorithm. | |
| 150 | + * See the KeyAgreement section in the <a href= | |
| 151 | + * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> | |
| 152 | + * Java Cryptography Architecture Standard Algorithm Name Documentation | |
| 153 | + * for information about standard algorithm names. | |
| 154 | + * | |
| 155 | + * @return the new <code>KeyAgreement</code> object. | |
| 156 | + * | |
| 157 | + * @exception NullPointerException if the specified algorithm | |
| 158 | + * is null. | |
| 159 | + * | |
| 160 | + * @exception NoSuchAlgorithmException if no Provider supports a | |
| 161 | + * KeyAgreementSpi implementation for the | |
| 162 | + * specified algorithm. | |
| 163 | + * | |
| 164 | + * @see java.security.Provider | |
| 165 | + */ | |
| 166 | + public static final KeyAgreement getInstance(String algorithm) | |
| 167 | + throws NoSuchAlgorithmException { | |
| 168 | + List services = GetInstance.getServices("KeyAgreement", algorithm); | |
| 169 | + // make sure there is at least one service from a signed provider | |
| 170 | + Iterator t = services.iterator(); | |
| 171 | + while (t.hasNext()) { | |
| 172 | + Service s = (Service)t.next(); | |
| 173 | + if (JceSecurity.canUseProvider(s.getProvider()) == false) { | |
| 174 | + continue; | |
| 175 | + } | |
| 176 | + return new KeyAgreement(s, t, algorithm); | |
| 177 | + } | |
| 178 | + throw new NoSuchAlgorithmException | |
| 179 | + ("Algorithm " + algorithm + " not available"); | |
| 180 | + } | |
| 181 | + | |
| 182 | + /** | |
| 183 | + * Returns a <code>KeyAgreement</code> object that implements the | |
| 184 | + * specified key agreement algorithm. | |
| 185 | + * | |
| 186 | + * <p> A new KeyAgreement object encapsulating the | |
| 187 | + * KeyAgreementSpi implementation from the specified provider | |
| 188 | + * is returned. The specified provider must be registered | |
| 189 | + * in the security provider list. | |
| 190 | + * | |
| 191 | + * <p> Note that the list of registered providers may be retrieved via | |
| 192 | + * the {@link Security#getProviders() Security.getProviders()} method. | |
| 193 | + * | |
| 194 | + * @param algorithm the standard name of the requested key agreement | |
| 195 | + * algorithm. | |
| 196 | + * See the KeyAgreement section in the <a href= | |
| 197 | + * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> | |
| 198 | + * Java Cryptography Architecture Standard Algorithm Name Documentation | |
| 199 | + * for information about standard algorithm names. | |
| 200 | + * | |
| 201 | + * @param provider the name of the provider. | |
| 202 | + * | |
| 203 | + * @return the new <code>KeyAgreement</code> object. | |
| 204 | + * | |
| 205 | + * @exception NullPointerException if the specified algorithm | |
| 206 | + * is null. | |
| 207 | + * | |
| 208 | + * @exception NoSuchAlgorithmException if a KeyAgreementSpi | |
| 209 | + * implementation for the specified algorithm is not | |
| 210 | + * available from the specified provider. | |
| 211 | + * | |
| 212 | + * @exception NoSuchProviderException if the specified provider is not | |
| 213 | + * registered in the security provider list. | |
| 214 | + * | |
| 215 | + * @exception IllegalArgumentException if the <code>provider</code> | |
| 216 | + * is null or empty. | |
| 217 | + * | |
| 218 | + * @see java.security.Provider | |
| 219 | + */ | |
| 220 | + public static final KeyAgreement getInstance(String algorithm, | |
| 221 | + String provider) throws NoSuchAlgorithmException, | |
| 222 | + NoSuchProviderException { | |
| 223 | + Instance instance = JceSecurity.getInstance | |
| 224 | + ("KeyAgreement", KeyAgreementSpi.class, algorithm, provider); | |
| 225 | + return new KeyAgreement((KeyAgreementSpi)instance.impl, | |
| 226 | + instance.provider, algorithm); | |
| 227 | + } | |
| 228 | + | |
| 229 | + /** | |
| 230 | + * Returns a <code>KeyAgreement</code> object that implements the | |
| 231 | + * specified key agreement algorithm. | |
| 232 | + * | |
| 233 | + * <p> A new KeyAgreement object encapsulating the | |
| 234 | + * KeyAgreementSpi implementation from the specified Provider | |
| 235 | + * object is returned. Note that the specified Provider object | |
| 236 | + * does not have to be registered in the provider list. | |
| 237 | + * | |
| 238 | + * @param algorithm the standard name of the requested key agreement | |
| 239 | + * algorithm. | |
| 240 | + * See the KeyAgreement section in the <a href= | |
| 241 | + * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> | |
| 242 | + * Java Cryptography Architecture Standard Algorithm Name Documentation | |
| 243 | + * for information about standard algorithm names. | |
| 244 | + * | |
| 245 | + * @param provider the provider. | |
| 246 | + * | |
| 247 | + * @return the new <code>KeyAgreement</code> object. | |
| 248 | + * | |
| 249 | + * @exception NullPointerException if the specified algorithm | |
| 250 | + * is null. | |
| 251 | + * | |
| 252 | + * @exception NoSuchAlgorithmException if a KeyAgreementSpi | |
| 253 | + * implementation for the specified algorithm is not available | |
| 254 | + * from the specified Provider object. | |
| 255 | + * | |
| 256 | + * @exception IllegalArgumentException if the <code>provider</code> | |
| 257 | + * is null. | |
| 258 | + * | |
| 259 | + * @see java.security.Provider | |
| 260 | + */ | |
| 261 | + public static final KeyAgreement getInstance(String algorithm, | |
| 262 | + Provider provider) throws NoSuchAlgorithmException { | |
| 263 | + Instance instance = JceSecurity.getInstance | |
| 264 | + ("KeyAgreement", KeyAgreementSpi.class, algorithm, provider); | |
| 265 | + return new KeyAgreement((KeyAgreementSpi)instance.impl, | |
| 266 | + instance.provider, algorithm); | |
| 267 | + } | |
| 268 | + | |
| 269 | + // max number of debug warnings to print from chooseFirstProvider() | |
| 270 | + private static int warnCount = 10; | |
| 271 | + | |
| 272 | + /** | |
| 273 | + * Choose the Spi from the first provider available. Used if | |
| 274 | + * delayed provider selection is not possible because init() | |
| 275 | + * is not the first method called. | |
| 276 | + */ | |
| 277 | + void chooseFirstProvider() { | |
| 278 | + if (spi != null) { | |
| 279 | + return; | |
| 280 | + } | |
| 281 | + synchronized (lock) { | |
| 282 | + if (spi != null) { | |
| 283 | + return; | |
| 284 | + } | |
| 285 | + if (debug != null) { | |
| 286 | + int w = --warnCount; | |
| 287 | + if (w >= 0) { | |
| 288 | + debug.println("KeyAgreement.init() not first method " | |
| 289 | + + "called, disabling delayed provider selection"); | |
| 290 | + if (w == 0) { | |
| 291 | + debug.println("Further warnings of this type will " | |
| 292 | + + "be suppressed"); | |
| 293 | + } | |
| 294 | + new Exception("Call trace").printStackTrace(); | |
| 295 | + } | |
| 296 | + } | |
| 297 | + Exception lastException = null; | |
| 298 | + while ((firstService != null) || serviceIterator.hasNext()) { | |
| 299 | + Service s; | |
| 300 | + if (firstService != null) { | |
| 301 | + s = firstService; | |
| 302 | + firstService = null; | |
| 303 | + } else { | |
| 304 | + s = (Service)serviceIterator.next(); | |
| 305 | + } | |
| 306 | + if (JceSecurity.canUseProvider(s.getProvider()) == false) { | |
| 307 | + continue; | |
| 308 | + } | |
| 309 | + try { | |
| 310 | + Object obj = s.newInstance(null); | |
| 311 | + if (obj instanceof KeyAgreementSpi == false) { | |
| 312 | + continue; | |
| 313 | + } | |
| 314 | + spi = (KeyAgreementSpi)obj; | |
| 315 | + provider = s.getProvider(); | |
| 316 | + // not needed any more | |
| 317 | + firstService = null; | |
| 318 | + serviceIterator = null; | |
| 319 | + return; | |
| 320 | + } catch (Exception e) { | |
| 321 | + lastException = e; | |
| 322 | + } | |
| 323 | + } | |
| 324 | + ProviderException e = new ProviderException | |
| 325 | + ("Could not construct KeyAgreementSpi instance"); | |
| 326 | + if (lastException != null) { | |
| 327 | + e.initCause(lastException); | |
| 328 | + } | |
| 329 | + throw e; | |
| 330 | + } | |
| 331 | + } | |
| 332 | + | |
| 333 | + private final static int I_NO_PARAMS = 1; | |
| 334 | + private final static int I_PARAMS = 2; | |
| 335 | + | |
| 336 | + private void implInit(KeyAgreementSpi spi, int type, Key key, | |
| 337 | + AlgorithmParameterSpec params, SecureRandom random) | |
| 338 | + throws InvalidKeyException, InvalidAlgorithmParameterException { | |
| 339 | + if (type == I_NO_PARAMS) { | |
| 340 | + spi.engineInit(key, random); | |
| 341 | + } else { // I_PARAMS | |
| 342 | + spi.engineInit(key, params, random); | |
| 343 | + } | |
| 344 | + } | |
| 345 | + | |
| 346 | + private void chooseProvider(int initType, Key key, | |
| 347 | + AlgorithmParameterSpec params, SecureRandom random) | |
| 348 | + throws InvalidKeyException, InvalidAlgorithmParameterException { | |
| 349 | + synchronized (lock) { | |
| 350 | + if (spi != null) { | |
| 351 | + implInit(spi, initType, key, params, random); | |
| 352 | + return; | |
| 353 | + } | |
| 354 | + Exception lastException = null; | |
| 355 | + while ((firstService != null) || serviceIterator.hasNext()) { | |
| 356 | + Service s; | |
| 357 | + if (firstService != null) { | |
| 358 | + s = firstService; | |
| 359 | + firstService = null; | |
| 360 | + } else { | |
| 361 | + s = (Service)serviceIterator.next(); | |
| 362 | + } | |
| 363 | + // if provider says it does not support this key, ignore it | |
| 364 | + if (s.supportsParameter(key) == false) { | |
| 365 | + continue; | |
| 366 | + } | |
| 367 | + if (JceSecurity.canUseProvider(s.getProvider()) == false) { | |
| 368 | + continue; | |
| 369 | + } | |
| 370 | + try { | |
| 371 | + KeyAgreementSpi spi = (KeyAgreementSpi)s.newInstance(null); | |
| 372 | + implInit(spi, initType, key, params, random); | |
| 373 | + provider = s.getProvider(); | |
| 374 | + this.spi = spi; | |
| 375 | + firstService = null; | |
| 376 | + serviceIterator = null; | |
| 377 | + return; | |
| 378 | + } catch (Exception e) { | |
| 379 | + // NoSuchAlgorithmException from newInstance() | |
| 380 | + // InvalidKeyException from init() | |
| 381 | + // RuntimeException (ProviderException) from init() | |
| 382 | + if (lastException == null) { | |
| 383 | + lastException = e; | |
| 384 | + } | |
| 385 | + } | |
| 386 | + } | |
| 387 | + // no working provider found, fail | |
| 388 | + if (lastException instanceof InvalidKeyException) { | |
| 389 | + throw (InvalidKeyException)lastException; | |
| 390 | + } | |
| 391 | + if (lastException instanceof InvalidAlgorithmParameterException) { | |
| 392 | + throw (InvalidAlgorithmParameterException)lastException; | |
| 393 | + } | |
| 394 | + if (lastException instanceof RuntimeException) { | |
| 395 | + throw (RuntimeException)lastException; | |
| 396 | + } | |
| 397 | + String kName = (key != null) ? key.getClass().getName() : "(null)"; | |
| 398 | + throw new InvalidKeyException | |
| 399 | + ("No installed provider supports this key: " | |
| 400 | + + kName, lastException); | |
| 401 | + } | |
| 402 | + } | |
| 403 | + | |
| 404 | + /** | |
| 405 | + * Returns the provider of this <code>KeyAgreement</code> object. | |
| 406 | + * | |
| 407 | + * @return the provider of this <code>KeyAgreement</code> object | |
| 408 | + */ | |
| 409 | + public final Provider getProvider() { | |
| 410 | + chooseFirstProvider(); | |
| 411 | + return this.provider; | |
| 412 | + } | |
| 413 | + | |
| 414 | + /** | |
| 415 | + * Initializes this key agreement with the given key, which is required to | |
| 416 | + * contain all the algorithm parameters required for this key agreement. | |
| 417 | + * | |
| 418 | + * <p> If this key agreement requires any random bytes, it will get | |
| 419 | + * them using the | |
| 420 | + * {@link SecureRandom <code>SecureRandom</code>} | |
| 421 | + * implementation of the highest-priority | |
| 422 | + * installed provider as the source of randomness. | |
| 423 | + * (If none of the installed providers supply an implementation of | |
| 424 | + * SecureRandom, a system-provided source of randomness will be used.) | |
| 425 | + * | |
| 426 | + * @param key the party's private information. For example, in the case | |
| 427 | + * of the Diffie-Hellman key agreement, this would be the party's own | |
| 428 | + * Diffie-Hellman private key. | |
| 429 | + * | |
| 430 | + * @exception InvalidKeyException if the given key is | |
| 431 | + * inappropriate for this key agreement, e.g., is of the wrong type or | |
| 432 | + * has an incompatible algorithm type. | |
| 433 | + */ | |
| 434 | + public final void init(Key key) throws InvalidKeyException { | |
| 435 | + init(key, JceSecurity.RANDOM); | |
| 436 | + } | |
| 437 | + | |
| 438 | + /** | |
| 439 | + * Initializes this key agreement with the given key and source of | |
| 440 | + * randomness. The given key is required to contain all the algorithm | |
| 441 | + * parameters required for this key agreement. | |
| 442 | + * | |
| 443 | + * <p> If the key agreement algorithm requires random bytes, it gets them | |
| 444 | + * from the given source of randomness, <code>random</code>. | |
| 445 | + * However, if the underlying | |
| 446 | + * algorithm implementation does not require any random bytes, | |
| 447 | + * <code>random</code> is ignored. | |
| 448 | + * | |
| 449 | + * @param key the party's private information. For example, in the case | |
| 450 | + * of the Diffie-Hellman key agreement, this would be the party's own | |
| 451 | + * Diffie-Hellman private key. | |
| 452 | + * @param random the source of randomness | |
| 453 | + * | |
| 454 | + * @exception InvalidKeyException if the given key is | |
| 455 | + * inappropriate for this key agreement, e.g., is of the wrong type or | |
| 456 | + * has an incompatible algorithm type. | |
| 457 | + */ | |
| 458 | + public final void init(Key key, SecureRandom random) | |
| 459 | + throws InvalidKeyException { | |
| 460 | + if (spi != null) { | |
| 461 | + spi.engineInit(key, random); | |
| 462 | + } else { | |
| 463 | + try { | |
| 464 | + chooseProvider(I_NO_PARAMS, key, null, random); | |
| 465 | + } catch (InvalidAlgorithmParameterException e) { | |
| 466 | + // should never occur | |
| 467 | + throw new InvalidKeyException(e); | |
| 468 | + } | |
| 469 | + } | |
| 470 | + } | |
| 471 | + | |
| 472 | + /** | |
| 473 | + * Initializes this key agreement with the given key and set of | |
| 474 | + * algorithm parameters. | |
| 475 | + * | |
| 476 | + * <p> If this key agreement requires any random bytes, it will get | |
| 477 | + * them using the | |
| 478 | + * {@link SecureRandom <code>SecureRandom</code>} | |
| 479 | + * implementation of the highest-priority | |
| 480 | + * installed provider as the source of randomness. | |
| 481 | + * (If none of the installed providers supply an implementation of | |
| 482 | + * SecureRandom, a system-provided source of randomness will be used.) | |
| 483 | + * | |
| 484 | + * @param key the party's private information. For example, in the case | |
| 485 | + * of the Diffie-Hellman key agreement, this would be the party's own | |
| 486 | + * Diffie-Hellman private key. | |
| 487 | + * @param params the key agreement parameters | |
| 488 | + * | |
| 489 | + * @exception InvalidKeyException if the given key is | |
| 490 | + * inappropriate for this key agreement, e.g., is of the wrong type or | |
| 491 | + * has an incompatible algorithm type. | |
| 492 | + * @exception InvalidAlgorithmParameterException if the given parameters | |
| 493 | + * are inappropriate for this key agreement. | |
| 494 | + */ | |
| 495 | + public final void init(Key key, AlgorithmParameterSpec params) | |
| 496 | + throws InvalidKeyException, InvalidAlgorithmParameterException | |
| 497 | + { | |
| 498 | + init(key, params, JceSecurity.RANDOM); | |
| 499 | + } | |
| 500 | + | |
| 501 | + /** | |
| 502 | + * Initializes this key agreement with the given key, set of | |
| 503 | + * algorithm parameters, and source of randomness. | |
| 504 | + * | |
| 505 | + * @param key the party's private information. For example, in the case | |
| 506 | + * of the Diffie-Hellman key agreement, this would be the party's own | |
| 507 | + * Diffie-Hellman private key. | |
| 508 | + * @param params the key agreement parameters | |
| 509 | + * @param random the source of randomness | |
| 510 | + * | |
| 511 | + * @exception InvalidKeyException if the given key is | |
| 512 | + * inappropriate for this key agreement, e.g., is of the wrong type or | |
| 513 | + * has an incompatible algorithm type. | |
| 514 | + * @exception InvalidAlgorithmParameterException if the given parameters | |
| 515 | + * are inappropriate for this key agreement. | |
| 516 | + */ | |
| 517 | + public final void init(Key key, AlgorithmParameterSpec params, | |
| 518 | + SecureRandom random) | |
| 519 | + throws InvalidKeyException, InvalidAlgorithmParameterException | |
| 520 | + { | |
| 521 | + if (spi != null) { | |
| 522 | + spi.engineInit(key, params, random); | |
| 523 | + } else { | |
| 524 | + chooseProvider(I_PARAMS, key, params, random); | |
| 525 | + } | |
| 526 | + } | |
| 527 | + | |
| 528 | + /** | |
| 529 | + * Executes the next phase of this key agreement with the given | |
| 530 | + * key that was received from one of the other parties involved in this key | |
| 531 | + * agreement. | |
| 532 | + * | |
| 533 | + * @param key the key for this phase. For example, in the case of | |
| 534 | + * Diffie-Hellman between 2 parties, this would be the other party's | |
| 535 | + * Diffie-Hellman public key. | |
| 536 | + * @param lastPhase flag which indicates whether or not this is the last | |
| 537 | + * phase of this key agreement. | |
| 538 | + * | |
| 539 | + * @return the (intermediate) key resulting from this phase, or null | |
| 540 | + * if this phase does not yield a key | |
| 541 | + * | |
| 542 | + * @exception InvalidKeyException if the given key is inappropriate for | |
| 543 | + * this phase. | |
| 544 | + * @exception IllegalStateException if this key agreement has not been | |
| 545 | + * initialized. | |
| 546 | + */ | |
| 547 | + public final Key doPhase(Key key, boolean lastPhase) | |
| 548 | + throws InvalidKeyException, IllegalStateException | |
| 549 | + { | |
| 550 | + chooseFirstProvider(); | |
| 551 | + return spi.engineDoPhase(key, lastPhase); | |
| 552 | + } | |
| 553 | + | |
| 554 | + /** | |
| 555 | + * Generates the shared secret and returns it in a new buffer. | |
| 556 | + * | |
| 557 | + * <p>This method resets this <code>KeyAgreement</code> object, so that it | |
| 558 | + * can be reused for further key agreements. Unless this key agreement is | |
| 559 | + * reinitialized with one of the <code>init</code> methods, the same | |
| 560 | + * private information and algorithm parameters will be used for | |
| 561 | + * subsequent key agreements. | |
| 562 | + * | |
| 563 | + * @return the new buffer with the shared secret | |
| 564 | + * | |
| 565 | + * @exception IllegalStateException if this key agreement has not been | |
| 566 | + * completed yet | |
| 567 | + */ | |
| 568 | + public final byte[] generateSecret() throws IllegalStateException { | |
| 569 | + chooseFirstProvider(); | |
| 570 | + return spi.engineGenerateSecret(); | |
| 571 | + } | |
| 572 | + | |
| 573 | + /** | |
| 574 | + * Generates the shared secret, and places it into the buffer | |
| 575 | + * <code>sharedSecret</code>, beginning at <code>offset</code> inclusive. | |
| 576 | + * | |
| 577 | + * <p>If the <code>sharedSecret</code> buffer is too small to hold the | |
| 578 | + * result, a <code>ShortBufferException</code> is thrown. | |
| 579 | + * In this case, this call should be repeated with a larger output buffer. | |
| 580 | + * | |
| 581 | + * <p>This method resets this <code>KeyAgreement</code> object, so that it | |
| 582 | + * can be reused for further key agreements. Unless this key agreement is | |
| 583 | + * reinitialized with one of the <code>init</code> methods, the same | |
| 584 | + * private information and algorithm parameters will be used for | |
| 585 | + * subsequent key agreements. | |
| 586 | + * | |
| 587 | + * @param sharedSecret the buffer for the shared secret | |
| 588 | + * @param offset the offset in <code>sharedSecret</code> where the | |
| 589 | + * shared secret will be stored | |
| 590 | + * | |
| 591 | + * @return the number of bytes placed into <code>sharedSecret</code> | |
| 592 | + * | |
| 593 | + * @exception IllegalStateException if this key agreement has not been | |
| 594 | + * completed yet | |
| 595 | + * @exception ShortBufferException if the given output buffer is too small | |
| 596 | + * to hold the secret | |
| 597 | + */ | |
| 598 | + public final int generateSecret(byte[] sharedSecret, int offset) | |
| 599 | + throws IllegalStateException, ShortBufferException | |
| 600 | + { | |
| 601 | + chooseFirstProvider(); | |
| 602 | + return spi.engineGenerateSecret(sharedSecret, offset); | |
| 603 | + } | |
| 604 | + | |
| 605 | + /** | |
| 606 | + * Creates the shared secret and returns it as a <code>SecretKey</code> | |
| 607 | + * object of the specified algorithm. | |
| 608 | + * | |
| 609 | + * <p>This method resets this <code>KeyAgreement</code> object, so that it | |
| 610 | + * can be reused for further key agreements. Unless this key agreement is | |
| 611 | + * reinitialized with one of the <code>init</code> methods, the same | |
| 612 | + * private information and algorithm parameters will be used for | |
| 613 | + * subsequent key agreements. | |
| 614 | + * | |
| 615 | + * @param algorithm the requested secret-key algorithm | |
| 616 | + * | |
| 617 | + * @return the shared secret key | |
| 618 | + * | |
| 619 | + * @exception IllegalStateException if this key agreement has not been | |
| 620 | + * completed yet | |
| 621 | + * @exception NoSuchAlgorithmException if the specified secret-key | |
| 622 | + * algorithm is not available | |
| 623 | + * @exception InvalidKeyException if the shared secret-key material cannot | |
| 624 | + * be used to generate a secret key of the specified algorithm (e.g., | |
| 625 | + * the key material is too short) | |
| 626 | + */ | |
| 627 | + public final SecretKey generateSecret(String algorithm) | |
| 628 | + throws IllegalStateException, NoSuchAlgorithmException, | |
| 629 | + InvalidKeyException | |
| 630 | + { | |
| 631 | + chooseFirstProvider(); | |
| 632 | + return spi.engineGenerateSecret(algorithm); | |
| 633 | + } | |
| 634 | +} | |