Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 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 | |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 90 | private final Object lock; |
| 91 | |
| 92 | /** |
| 93 | * Creates a KeyAgreement object. |
| 94 | * |
| 95 | * @param keyAgreeSpi the delegate |
| 96 | * @param provider the provider |
| 97 | * @param algorithm the algorithm |
| 98 | */ |
| 99 | protected KeyAgreement(KeyAgreementSpi keyAgreeSpi, Provider provider, |
| 100 | String algorithm) { |
| 101 | this.spi = keyAgreeSpi; |
| 102 | this.provider = provider; |
| 103 | this.algorithm = algorithm; |
| 104 | lock = null; |
| 105 | } |
| 106 | |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 107 | private KeyAgreement(String algorithm) { |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 108 | this.algorithm = algorithm; |
| 109 | lock = new Object(); |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Returns the algorithm name of this <code>KeyAgreement</code> object. |
| 114 | * |
| 115 | * <p>This is the same name that was specified in one of the |
| 116 | * <code>getInstance</code> calls that created this |
| 117 | * <code>KeyAgreement</code> object. |
| 118 | * |
| 119 | * @return the algorithm name of this <code>KeyAgreement</code> object. |
| 120 | */ |
| 121 | public final String getAlgorithm() { |
| 122 | return this.algorithm; |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Returns a <code>KeyAgreement</code> object that implements the |
| 127 | * specified key agreement algorithm. |
| 128 | * |
| 129 | * <p> This method traverses the list of registered security Providers, |
| 130 | * starting with the most preferred Provider. |
| 131 | * A new KeyAgreement object encapsulating the |
| 132 | * KeyAgreementSpi implementation from the first |
| 133 | * Provider that supports the specified algorithm is returned. |
| 134 | * |
| 135 | * <p> Note that the list of registered providers may be retrieved via |
| 136 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 137 | * |
| 138 | * @param algorithm the standard name of the requested key agreement |
| 139 | * algorithm. |
| 140 | * See the KeyAgreement section in the <a href= |
| 141 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> |
| 142 | * Java Cryptography Architecture Standard Algorithm Name Documentation |
| 143 | * for information about standard algorithm names. |
| 144 | * |
| 145 | * @return the new <code>KeyAgreement</code> object. |
| 146 | * |
| 147 | * @exception NullPointerException if the specified algorithm |
| 148 | * is null. |
| 149 | * |
| 150 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 151 | * KeyAgreementSpi implementation for the |
| 152 | * specified algorithm. |
| 153 | * |
| 154 | * @see java.security.Provider |
| 155 | */ |
| 156 | public static final KeyAgreement getInstance(String algorithm) |
| 157 | throws NoSuchAlgorithmException { |
| 158 | List services = GetInstance.getServices("KeyAgreement", algorithm); |
| 159 | // make sure there is at least one service from a signed provider |
| 160 | Iterator t = services.iterator(); |
| 161 | while (t.hasNext()) { |
| 162 | Service s = (Service)t.next(); |
| 163 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 164 | continue; |
| 165 | } |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 166 | return new KeyAgreement(algorithm); |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 167 | } |
| 168 | throw new NoSuchAlgorithmException |
| 169 | ("Algorithm " + algorithm + " not available"); |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Returns a <code>KeyAgreement</code> object that implements the |
| 174 | * specified key agreement algorithm. |
| 175 | * |
| 176 | * <p> A new KeyAgreement object encapsulating the |
| 177 | * KeyAgreementSpi implementation from the specified provider |
| 178 | * is returned. The specified provider must be registered |
| 179 | * in the security provider list. |
| 180 | * |
| 181 | * <p> Note that the list of registered providers may be retrieved via |
| 182 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 183 | * |
| 184 | * @param algorithm the standard name of the requested key agreement |
| 185 | * algorithm. |
| 186 | * See the KeyAgreement section in the <a href= |
| 187 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> |
| 188 | * Java Cryptography Architecture Standard Algorithm Name Documentation |
| 189 | * for information about standard algorithm names. |
| 190 | * |
| 191 | * @param provider the name of the provider. |
| 192 | * |
| 193 | * @return the new <code>KeyAgreement</code> object. |
| 194 | * |
| 195 | * @exception NullPointerException if the specified algorithm |
| 196 | * is null. |
| 197 | * |
| 198 | * @exception NoSuchAlgorithmException if a KeyAgreementSpi |
| 199 | * implementation for the specified algorithm is not |
| 200 | * available from the specified provider. |
| 201 | * |
| 202 | * @exception NoSuchProviderException if the specified provider is not |
| 203 | * registered in the security provider list. |
| 204 | * |
| 205 | * @exception IllegalArgumentException if the <code>provider</code> |
| 206 | * is null or empty. |
| 207 | * |
| 208 | * @see java.security.Provider |
| 209 | */ |
| 210 | public static final KeyAgreement getInstance(String algorithm, |
| 211 | String provider) throws NoSuchAlgorithmException, |
| 212 | NoSuchProviderException { |
| 213 | Instance instance = JceSecurity.getInstance |
| 214 | ("KeyAgreement", KeyAgreementSpi.class, algorithm, provider); |
| 215 | return new KeyAgreement((KeyAgreementSpi)instance.impl, |
| 216 | instance.provider, algorithm); |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * Returns a <code>KeyAgreement</code> object that implements the |
| 221 | * specified key agreement algorithm. |
| 222 | * |
| 223 | * <p> A new KeyAgreement object encapsulating the |
| 224 | * KeyAgreementSpi implementation from the specified Provider |
| 225 | * object is returned. Note that the specified Provider object |
| 226 | * does not have to be registered in the provider list. |
| 227 | * |
| 228 | * @param algorithm the standard name of the requested key agreement |
| 229 | * algorithm. |
| 230 | * See the KeyAgreement section in the <a href= |
| 231 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyAgreement"> |
| 232 | * Java Cryptography Architecture Standard Algorithm Name Documentation |
| 233 | * for information about standard algorithm names. |
| 234 | * |
| 235 | * @param provider the provider. |
| 236 | * |
| 237 | * @return the new <code>KeyAgreement</code> object. |
| 238 | * |
| 239 | * @exception NullPointerException if the specified algorithm |
| 240 | * is null. |
| 241 | * |
| 242 | * @exception NoSuchAlgorithmException if a KeyAgreementSpi |
| 243 | * implementation for the specified algorithm is not available |
| 244 | * from the specified Provider object. |
| 245 | * |
| 246 | * @exception IllegalArgumentException if the <code>provider</code> |
| 247 | * is null. |
| 248 | * |
| 249 | * @see java.security.Provider |
| 250 | */ |
| 251 | public static final KeyAgreement getInstance(String algorithm, |
| 252 | Provider provider) throws NoSuchAlgorithmException { |
| 253 | Instance instance = JceSecurity.getInstance |
| 254 | ("KeyAgreement", KeyAgreementSpi.class, algorithm, provider); |
| 255 | return new KeyAgreement((KeyAgreementSpi)instance.impl, |
| 256 | instance.provider, algorithm); |
| 257 | } |
| 258 | |
| 259 | // max number of debug warnings to print from chooseFirstProvider() |
| 260 | private static int warnCount = 10; |
| 261 | |
| 262 | /** |
| 263 | * Choose the Spi from the first provider available. Used if |
| 264 | * delayed provider selection is not possible because init() |
| 265 | * is not the first method called. |
| 266 | */ |
| 267 | void chooseFirstProvider() { |
| 268 | if (spi != null) { |
| 269 | return; |
| 270 | } |
| 271 | synchronized (lock) { |
| 272 | if (spi != null) { |
| 273 | return; |
| 274 | } |
| 275 | if (debug != null) { |
| 276 | int w = --warnCount; |
| 277 | if (w >= 0) { |
| 278 | debug.println("KeyAgreement.init() not first method " |
| 279 | + "called, disabling delayed provider selection"); |
| 280 | if (w == 0) { |
| 281 | debug.println("Further warnings of this type will " |
| 282 | + "be suppressed"); |
| 283 | } |
| 284 | new Exception("Call trace").printStackTrace(); |
| 285 | } |
| 286 | } |
| 287 | Exception lastException = null; |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 288 | for (Service s : GetInstance.getServices("KeyAgreement", algorithm)) { |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 289 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 290 | continue; |
| 291 | } |
| 292 | try { |
| 293 | Object obj = s.newInstance(null); |
| 294 | if (obj instanceof KeyAgreementSpi == false) { |
| 295 | continue; |
| 296 | } |
| 297 | spi = (KeyAgreementSpi)obj; |
| 298 | provider = s.getProvider(); |
| 299 | // not needed any more |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 300 | return; |
| 301 | } catch (Exception e) { |
| 302 | lastException = e; |
| 303 | } |
| 304 | } |
| 305 | ProviderException e = new ProviderException |
| 306 | ("Could not construct KeyAgreementSpi instance"); |
| 307 | if (lastException != null) { |
| 308 | e.initCause(lastException); |
| 309 | } |
| 310 | throw e; |
| 311 | } |
| 312 | } |
| 313 | |
| 314 | private final static int I_NO_PARAMS = 1; |
| 315 | private final static int I_PARAMS = 2; |
| 316 | |
| 317 | private void implInit(KeyAgreementSpi spi, int type, Key key, |
| 318 | AlgorithmParameterSpec params, SecureRandom random) |
| 319 | throws InvalidKeyException, InvalidAlgorithmParameterException { |
| 320 | if (type == I_NO_PARAMS) { |
| 321 | spi.engineInit(key, random); |
| 322 | } else { // I_PARAMS |
| 323 | spi.engineInit(key, params, random); |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | private void chooseProvider(int initType, Key key, |
| 328 | AlgorithmParameterSpec params, SecureRandom random) |
| 329 | throws InvalidKeyException, InvalidAlgorithmParameterException { |
| 330 | synchronized (lock) { |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 331 | if (spi != null && key == null) { |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 332 | implInit(spi, initType, key, params, random); |
| 333 | return; |
| 334 | } |
| 335 | Exception lastException = null; |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 336 | for (Service s : GetInstance.getServices("KeyAgreement", algorithm)) { |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 337 | // if provider says it does not support this key, ignore it |
| 338 | if (s.supportsParameter(key) == false) { |
| 339 | continue; |
| 340 | } |
| 341 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 342 | continue; |
| 343 | } |
| 344 | try { |
| 345 | KeyAgreementSpi spi = (KeyAgreementSpi)s.newInstance(null); |
| 346 | implInit(spi, initType, key, params, random); |
| 347 | provider = s.getProvider(); |
| 348 | this.spi = spi; |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 349 | return; |
| 350 | } catch (Exception e) { |
| 351 | // NoSuchAlgorithmException from newInstance() |
| 352 | // InvalidKeyException from init() |
| 353 | // RuntimeException (ProviderException) from init() |
| 354 | if (lastException == null) { |
| 355 | lastException = e; |
| 356 | } |
| 357 | } |
| 358 | } |
| 359 | // no working provider found, fail |
| 360 | if (lastException instanceof InvalidKeyException) { |
| 361 | throw (InvalidKeyException)lastException; |
| 362 | } |
| 363 | if (lastException instanceof InvalidAlgorithmParameterException) { |
| 364 | throw (InvalidAlgorithmParameterException)lastException; |
| 365 | } |
| 366 | if (lastException instanceof RuntimeException) { |
| 367 | throw (RuntimeException)lastException; |
| 368 | } |
| 369 | String kName = (key != null) ? key.getClass().getName() : "(null)"; |
| 370 | throw new InvalidKeyException |
| 371 | ("No installed provider supports this key: " |
| 372 | + kName, lastException); |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | /** |
| 377 | * Returns the provider of this <code>KeyAgreement</code> object. |
| 378 | * |
| 379 | * @return the provider of this <code>KeyAgreement</code> object |
| 380 | */ |
| 381 | public final Provider getProvider() { |
| 382 | chooseFirstProvider(); |
| 383 | return this.provider; |
| 384 | } |
| 385 | |
| 386 | /** |
| 387 | * Initializes this key agreement with the given key, which is required to |
| 388 | * contain all the algorithm parameters required for this key agreement. |
| 389 | * |
| 390 | * <p> If this key agreement requires any random bytes, it will get |
| 391 | * them using the |
| 392 | * {@link SecureRandom <code>SecureRandom</code>} |
| 393 | * implementation of the highest-priority |
| 394 | * installed provider as the source of randomness. |
| 395 | * (If none of the installed providers supply an implementation of |
| 396 | * SecureRandom, a system-provided source of randomness will be used.) |
| 397 | * |
| 398 | * @param key the party's private information. For example, in the case |
| 399 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 400 | * Diffie-Hellman private key. |
| 401 | * |
| 402 | * @exception InvalidKeyException if the given key is |
| 403 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 404 | * has an incompatible algorithm type. |
| 405 | */ |
| 406 | public final void init(Key key) throws InvalidKeyException { |
| 407 | init(key, JceSecurity.RANDOM); |
| 408 | } |
| 409 | |
| 410 | /** |
| 411 | * Initializes this key agreement with the given key and source of |
| 412 | * randomness. The given key is required to contain all the algorithm |
| 413 | * parameters required for this key agreement. |
| 414 | * |
| 415 | * <p> If the key agreement algorithm requires random bytes, it gets them |
| 416 | * from the given source of randomness, <code>random</code>. |
| 417 | * However, if the underlying |
| 418 | * algorithm implementation does not require any random bytes, |
| 419 | * <code>random</code> is ignored. |
| 420 | * |
| 421 | * @param key the party's private information. For example, in the case |
| 422 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 423 | * Diffie-Hellman private key. |
| 424 | * @param random the source of randomness |
| 425 | * |
| 426 | * @exception InvalidKeyException if the given key is |
| 427 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 428 | * has an incompatible algorithm type. |
| 429 | */ |
| 430 | public final void init(Key key, SecureRandom random) |
| 431 | throws InvalidKeyException { |
Piotr Jastrzebski | 875528b | 2015-04-10 12:23:00 +0100 | [diff] [blame^] | 432 | if (spi != null && (key == null || lock == null)) { |
Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 433 | spi.engineInit(key, random); |
| 434 | } else { |
| 435 | try { |
| 436 | chooseProvider(I_NO_PARAMS, key, null, random); |
| 437 | } catch (InvalidAlgorithmParameterException e) { |
| 438 | // should never occur |
| 439 | throw new InvalidKeyException(e); |
| 440 | } |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | /** |
| 445 | * Initializes this key agreement with the given key and set of |
| 446 | * algorithm parameters. |
| 447 | * |
| 448 | * <p> If this key agreement requires any random bytes, it will get |
| 449 | * them using the |
| 450 | * {@link SecureRandom <code>SecureRandom</code>} |
| 451 | * implementation of the highest-priority |
| 452 | * installed provider as the source of randomness. |
| 453 | * (If none of the installed providers supply an implementation of |
| 454 | * SecureRandom, a system-provided source of randomness will be used.) |
| 455 | * |
| 456 | * @param key the party's private information. For example, in the case |
| 457 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 458 | * Diffie-Hellman private key. |
| 459 | * @param params the key agreement parameters |
| 460 | * |
| 461 | * @exception InvalidKeyException if the given key is |
| 462 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 463 | * has an incompatible algorithm type. |
| 464 | * @exception InvalidAlgorithmParameterException if the given parameters |
| 465 | * are inappropriate for this key agreement. |
| 466 | */ |
| 467 | public final void init(Key key, AlgorithmParameterSpec params) |
| 468 | throws InvalidKeyException, InvalidAlgorithmParameterException |
| 469 | { |
| 470 | init(key, params, JceSecurity.RANDOM); |
| 471 | } |
| 472 | |
| 473 | /** |
| 474 | * Initializes this key agreement with the given key, set of |
| 475 | * algorithm parameters, and source of randomness. |
| 476 | * |
| 477 | * @param key the party's private information. For example, in the case |
| 478 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 479 | * Diffie-Hellman private key. |
| 480 | * @param params the key agreement parameters |
| 481 | * @param random the source of randomness |
| 482 | * |
| 483 | * @exception InvalidKeyException if the given key is |
| 484 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 485 | * has an incompatible algorithm type. |
| 486 | * @exception InvalidAlgorithmParameterException if the given parameters |
| 487 | * are inappropriate for this key agreement. |
| 488 | */ |
| 489 | public final void init(Key key, AlgorithmParameterSpec params, |
| 490 | SecureRandom random) |
| 491 | throws InvalidKeyException, InvalidAlgorithmParameterException |
| 492 | { |
| 493 | if (spi != null) { |
| 494 | spi.engineInit(key, params, random); |
| 495 | } else { |
| 496 | chooseProvider(I_PARAMS, key, params, random); |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | /** |
| 501 | * Executes the next phase of this key agreement with the given |
| 502 | * key that was received from one of the other parties involved in this key |
| 503 | * agreement. |
| 504 | * |
| 505 | * @param key the key for this phase. For example, in the case of |
| 506 | * Diffie-Hellman between 2 parties, this would be the other party's |
| 507 | * Diffie-Hellman public key. |
| 508 | * @param lastPhase flag which indicates whether or not this is the last |
| 509 | * phase of this key agreement. |
| 510 | * |
| 511 | * @return the (intermediate) key resulting from this phase, or null |
| 512 | * if this phase does not yield a key |
| 513 | * |
| 514 | * @exception InvalidKeyException if the given key is inappropriate for |
| 515 | * this phase. |
| 516 | * @exception IllegalStateException if this key agreement has not been |
| 517 | * initialized. |
| 518 | */ |
| 519 | public final Key doPhase(Key key, boolean lastPhase) |
| 520 | throws InvalidKeyException, IllegalStateException |
| 521 | { |
| 522 | chooseFirstProvider(); |
| 523 | return spi.engineDoPhase(key, lastPhase); |
| 524 | } |
| 525 | |
| 526 | /** |
| 527 | * Generates the shared secret and returns it in a new buffer. |
| 528 | * |
| 529 | * <p>This method resets this <code>KeyAgreement</code> object, so that it |
| 530 | * can be reused for further key agreements. Unless this key agreement is |
| 531 | * reinitialized with one of the <code>init</code> methods, the same |
| 532 | * private information and algorithm parameters will be used for |
| 533 | * subsequent key agreements. |
| 534 | * |
| 535 | * @return the new buffer with the shared secret |
| 536 | * |
| 537 | * @exception IllegalStateException if this key agreement has not been |
| 538 | * completed yet |
| 539 | */ |
| 540 | public final byte[] generateSecret() throws IllegalStateException { |
| 541 | chooseFirstProvider(); |
| 542 | return spi.engineGenerateSecret(); |
| 543 | } |
| 544 | |
| 545 | /** |
| 546 | * Generates the shared secret, and places it into the buffer |
| 547 | * <code>sharedSecret</code>, beginning at <code>offset</code> inclusive. |
| 548 | * |
| 549 | * <p>If the <code>sharedSecret</code> buffer is too small to hold the |
| 550 | * result, a <code>ShortBufferException</code> is thrown. |
| 551 | * In this case, this call should be repeated with a larger output buffer. |
| 552 | * |
| 553 | * <p>This method resets this <code>KeyAgreement</code> object, so that it |
| 554 | * can be reused for further key agreements. Unless this key agreement is |
| 555 | * reinitialized with one of the <code>init</code> methods, the same |
| 556 | * private information and algorithm parameters will be used for |
| 557 | * subsequent key agreements. |
| 558 | * |
| 559 | * @param sharedSecret the buffer for the shared secret |
| 560 | * @param offset the offset in <code>sharedSecret</code> where the |
| 561 | * shared secret will be stored |
| 562 | * |
| 563 | * @return the number of bytes placed into <code>sharedSecret</code> |
| 564 | * |
| 565 | * @exception IllegalStateException if this key agreement has not been |
| 566 | * completed yet |
| 567 | * @exception ShortBufferException if the given output buffer is too small |
| 568 | * to hold the secret |
| 569 | */ |
| 570 | public final int generateSecret(byte[] sharedSecret, int offset) |
| 571 | throws IllegalStateException, ShortBufferException |
| 572 | { |
| 573 | chooseFirstProvider(); |
| 574 | return spi.engineGenerateSecret(sharedSecret, offset); |
| 575 | } |
| 576 | |
| 577 | /** |
| 578 | * Creates the shared secret and returns it as a <code>SecretKey</code> |
| 579 | * object of the specified algorithm. |
| 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 algorithm the requested secret-key algorithm |
| 588 | * |
| 589 | * @return the shared secret key |
| 590 | * |
| 591 | * @exception IllegalStateException if this key agreement has not been |
| 592 | * completed yet |
| 593 | * @exception NoSuchAlgorithmException if the specified secret-key |
| 594 | * algorithm is not available |
| 595 | * @exception InvalidKeyException if the shared secret-key material cannot |
| 596 | * be used to generate a secret key of the specified algorithm (e.g., |
| 597 | * the key material is too short) |
| 598 | */ |
| 599 | public final SecretKey generateSecret(String algorithm) |
| 600 | throws IllegalStateException, NoSuchAlgorithmException, |
| 601 | InvalidKeyException |
| 602 | { |
| 603 | chooseFirstProvider(); |
| 604 | return spi.engineGenerateSecret(algorithm); |
| 605 | } |
| 606 | } |