J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2006 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 | |
| 30 | import java.security.Provider.Service; |
| 31 | import java.security.spec.KeySpec; |
| 32 | import java.security.spec.InvalidKeySpecException; |
| 33 | |
| 34 | import sun.security.util.Debug; |
| 35 | import sun.security.jca.*; |
| 36 | import sun.security.jca.GetInstance.Instance; |
| 37 | |
| 38 | /** |
| 39 | * Key factories are used to convert <I>keys</I> (opaque |
| 40 | * cryptographic keys of type <code>Key</code>) into <I>key specifications</I> |
| 41 | * (transparent representations of the underlying key material), and vice |
| 42 | * versa. |
| 43 | * |
| 44 | * <P> Key factories are bi-directional. That is, they allow you to build an |
| 45 | * opaque key object from a given key specification (key material), or to |
| 46 | * retrieve the underlying key material of a key object in a suitable format. |
| 47 | * |
| 48 | * <P> Multiple compatible key specifications may exist for the same key. |
| 49 | * For example, a DSA public key may be specified using |
| 50 | * <code>DSAPublicKeySpec</code> or |
| 51 | * <code>X509EncodedKeySpec</code>. A key factory can be used to translate |
| 52 | * between compatible key specifications. |
| 53 | * |
| 54 | * <P> The following is an example of how to use a key factory in order to |
| 55 | * instantiate a DSA public key from its encoding. |
| 56 | * Assume Alice has received a digital signature from Bob. |
| 57 | * Bob also sent her his public key (in encoded format) to verify |
| 58 | * his signature. Alice then performs the following actions: |
| 59 | * |
| 60 | * <pre> |
| 61 | * X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(bobEncodedPubKey); |
| 62 | * KeyFactory keyFactory = KeyFactory.getInstance("DSA"); |
| 63 | * PublicKey bobPubKey = keyFactory.generatePublic(bobPubKeySpec); |
| 64 | * Signature sig = Signature.getInstance("DSA"); |
| 65 | * sig.initVerify(bobPubKey); |
| 66 | * sig.update(data); |
| 67 | * sig.verify(signature); |
| 68 | * </pre> |
| 69 | * |
| 70 | * @author Jan Luehe |
| 71 | * |
| 72 | * |
| 73 | * @see Key |
| 74 | * @see PublicKey |
| 75 | * @see PrivateKey |
| 76 | * @see java.security.spec.KeySpec |
| 77 | * @see java.security.spec.DSAPublicKeySpec |
| 78 | * @see java.security.spec.X509EncodedKeySpec |
| 79 | * |
| 80 | * @since 1.2 |
| 81 | */ |
| 82 | |
| 83 | public class KeyFactory { |
| 84 | |
| 85 | private static final Debug debug = |
| 86 | Debug.getInstance("jca", "KeyFactory"); |
| 87 | |
| 88 | // The algorithm associated with this key factory |
| 89 | private final String algorithm; |
| 90 | |
| 91 | // The provider |
| 92 | private Provider provider; |
| 93 | |
| 94 | // The provider implementation (delegate) |
| 95 | private volatile KeyFactorySpi spi; |
| 96 | |
| 97 | // lock for mutex during provider selection |
| 98 | private final Object lock = new Object(); |
| 99 | |
| 100 | // remaining services to try in provider selection |
| 101 | // null once provider is selected |
| 102 | private Iterator<Service> serviceIterator; |
| 103 | |
| 104 | /** |
| 105 | * Creates a KeyFactory object. |
| 106 | * |
| 107 | * @param keyFacSpi the delegate |
| 108 | * @param provider the provider |
| 109 | * @param algorithm the name of the algorithm |
| 110 | * to associate with this <tt>KeyFactory</tt> |
| 111 | */ |
| 112 | protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider, |
| 113 | String algorithm) { |
| 114 | this.spi = keyFacSpi; |
| 115 | this.provider = provider; |
| 116 | this.algorithm = algorithm; |
| 117 | } |
| 118 | |
| 119 | private KeyFactory(String algorithm) throws NoSuchAlgorithmException { |
| 120 | this.algorithm = algorithm; |
| 121 | List<Service> list = GetInstance.getServices("KeyFactory", algorithm); |
| 122 | serviceIterator = list.iterator(); |
| 123 | // fetch and instantiate initial spi |
| 124 | if (nextSpi(null) == null) { |
| 125 | throw new NoSuchAlgorithmException |
| 126 | (algorithm + " KeyFactory not available"); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * Returns a KeyFactory object that converts |
| 132 | * public/private keys of the specified algorithm. |
| 133 | * |
| 134 | * <p> This method traverses the list of registered security Providers, |
| 135 | * starting with the most preferred Provider. |
| 136 | * A new KeyFactory object encapsulating the |
| 137 | * KeyFactorySpi implementation from the first |
| 138 | * Provider that supports the specified algorithm is returned. |
| 139 | * |
| 140 | * <p> Note that the list of registered providers may be retrieved via |
| 141 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 142 | * |
| 143 | * @param algorithm the name of the requested key algorithm. |
| 144 | * See Appendix A in the <a href= |
| 145 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 146 | * Java Cryptography Architecture API Specification & Reference </a> |
| 147 | * for information about standard algorithm names. |
| 148 | * |
| 149 | * @return the new KeyFactory object. |
| 150 | * |
| 151 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 152 | * KeyFactorySpi implementation for the |
| 153 | * specified algorithm. |
| 154 | * |
| 155 | * @see Provider |
| 156 | */ |
| 157 | public static KeyFactory getInstance(String algorithm) |
| 158 | throws NoSuchAlgorithmException { |
| 159 | return new KeyFactory(algorithm); |
| 160 | } |
| 161 | |
| 162 | /** |
| 163 | * Returns a KeyFactory object that converts |
| 164 | * public/private keys of the specified algorithm. |
| 165 | * |
| 166 | * <p> A new KeyFactory object encapsulating the |
| 167 | * KeyFactorySpi implementation from the specified provider |
| 168 | * is returned. The specified provider must be registered |
| 169 | * in the security provider list. |
| 170 | * |
| 171 | * <p> Note that the list of registered providers may be retrieved via |
| 172 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 173 | * |
| 174 | * @param algorithm the name of the requested key algorithm. |
| 175 | * See Appendix A in the <a href= |
| 176 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 177 | * Java Cryptography Architecture API Specification & Reference </a> |
| 178 | * for information about standard algorithm names. |
| 179 | * |
| 180 | * @param provider the name of the provider. |
| 181 | * |
| 182 | * @return the new KeyFactory object. |
| 183 | * |
| 184 | * @exception NoSuchAlgorithmException if a KeyFactorySpi |
| 185 | * implementation for the specified algorithm is not |
| 186 | * available from the specified provider. |
| 187 | * |
| 188 | * @exception NoSuchProviderException if the specified provider is not |
| 189 | * registered in the security provider list. |
| 190 | * |
| 191 | * @exception IllegalArgumentException if the provider name is null |
| 192 | * or empty. |
| 193 | * |
| 194 | * @see Provider |
| 195 | */ |
| 196 | public static KeyFactory getInstance(String algorithm, String provider) |
| 197 | throws NoSuchAlgorithmException, NoSuchProviderException { |
| 198 | Instance instance = GetInstance.getInstance("KeyFactory", |
| 199 | KeyFactorySpi.class, algorithm, provider); |
| 200 | return new KeyFactory((KeyFactorySpi)instance.impl, |
| 201 | instance.provider, algorithm); |
| 202 | } |
| 203 | |
| 204 | /** |
| 205 | * Returns a KeyFactory object that converts |
| 206 | * public/private keys of the specified algorithm. |
| 207 | * |
| 208 | * <p> A new KeyFactory object encapsulating the |
| 209 | * KeyFactorySpi implementation from the specified Provider |
| 210 | * object is returned. Note that the specified Provider object |
| 211 | * does not have to be registered in the provider list. |
| 212 | * |
| 213 | * @param algorithm the name of the requested key algorithm. |
| 214 | * See Appendix A in the <a href= |
| 215 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 216 | * Java Cryptography Architecture API Specification & Reference </a> |
| 217 | * for information about standard algorithm names. |
| 218 | * |
| 219 | * @param provider the provider. |
| 220 | * |
| 221 | * @return the new KeyFactory object. |
| 222 | * |
| 223 | * @exception NoSuchAlgorithmException if a KeyFactorySpi |
| 224 | * implementation for the specified algorithm is not available |
| 225 | * from the specified Provider object. |
| 226 | * |
| 227 | * @exception IllegalArgumentException if the specified provider is null. |
| 228 | * |
| 229 | * @see Provider |
| 230 | * |
| 231 | * @since 1.4 |
| 232 | */ |
| 233 | public static KeyFactory getInstance(String algorithm, Provider provider) |
| 234 | throws NoSuchAlgorithmException { |
| 235 | Instance instance = GetInstance.getInstance("KeyFactory", |
| 236 | KeyFactorySpi.class, algorithm, provider); |
| 237 | return new KeyFactory((KeyFactorySpi)instance.impl, |
| 238 | instance.provider, algorithm); |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * Returns the provider of this key factory object. |
| 243 | * |
| 244 | * @return the provider of this key factory object |
| 245 | */ |
| 246 | public final Provider getProvider() { |
| 247 | synchronized (lock) { |
| 248 | // disable further failover after this call |
| 249 | serviceIterator = null; |
| 250 | return provider; |
| 251 | } |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * Gets the name of the algorithm |
| 256 | * associated with this <tt>KeyFactory</tt>. |
| 257 | * |
| 258 | * @return the name of the algorithm associated with this |
| 259 | * <tt>KeyFactory</tt> |
| 260 | */ |
| 261 | public final String getAlgorithm() { |
| 262 | return this.algorithm; |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * Update the active KeyFactorySpi of this class and return the next |
| 267 | * implementation for failover. If no more implemenations are |
| 268 | * available, this method returns null. However, the active spi of |
| 269 | * this class is never set to null. |
| 270 | */ |
| 271 | private KeyFactorySpi nextSpi(KeyFactorySpi oldSpi) { |
| 272 | synchronized (lock) { |
| 273 | // somebody else did a failover concurrently |
| 274 | // try that spi now |
| 275 | if ((oldSpi != null) && (oldSpi != spi)) { |
| 276 | return spi; |
| 277 | } |
| 278 | if (serviceIterator == null) { |
| 279 | return null; |
| 280 | } |
| 281 | while (serviceIterator.hasNext()) { |
| 282 | Service s = serviceIterator.next(); |
| 283 | try { |
| 284 | Object obj = s.newInstance(null); |
| 285 | if (obj instanceof KeyFactorySpi == false) { |
| 286 | continue; |
| 287 | } |
| 288 | KeyFactorySpi spi = (KeyFactorySpi)obj; |
| 289 | provider = s.getProvider(); |
| 290 | this.spi = spi; |
| 291 | return spi; |
| 292 | } catch (NoSuchAlgorithmException e) { |
| 293 | // ignore |
| 294 | } |
| 295 | } |
| 296 | serviceIterator = null; |
| 297 | return null; |
| 298 | } |
| 299 | } |
| 300 | |
| 301 | /** |
| 302 | * Generates a public key object from the provided key specification |
| 303 | * (key material). |
| 304 | * |
| 305 | * @param keySpec the specification (key material) of the public key. |
| 306 | * |
| 307 | * @return the public key. |
| 308 | * |
| 309 | * @exception InvalidKeySpecException if the given key specification |
| 310 | * is inappropriate for this key factory to produce a public key. |
| 311 | */ |
| 312 | public final PublicKey generatePublic(KeySpec keySpec) |
| 313 | throws InvalidKeySpecException { |
| 314 | if (serviceIterator == null) { |
| 315 | return spi.engineGeneratePublic(keySpec); |
| 316 | } |
| 317 | Exception failure = null; |
| 318 | KeyFactorySpi mySpi = spi; |
| 319 | do { |
| 320 | try { |
| 321 | return mySpi.engineGeneratePublic(keySpec); |
| 322 | } catch (Exception e) { |
| 323 | if (failure == null) { |
| 324 | failure = e; |
| 325 | } |
| 326 | mySpi = nextSpi(mySpi); |
| 327 | } |
| 328 | } while (mySpi != null); |
| 329 | if (failure instanceof RuntimeException) { |
| 330 | throw (RuntimeException)failure; |
| 331 | } |
| 332 | if (failure instanceof InvalidKeySpecException) { |
| 333 | throw (InvalidKeySpecException)failure; |
| 334 | } |
| 335 | throw new InvalidKeySpecException |
| 336 | ("Could not generate public key", failure); |
| 337 | } |
| 338 | |
| 339 | /** |
| 340 | * Generates a private key object from the provided key specification |
| 341 | * (key material). |
| 342 | * |
| 343 | * @param keySpec the specification (key material) of the private key. |
| 344 | * |
| 345 | * @return the private key. |
| 346 | * |
| 347 | * @exception InvalidKeySpecException if the given key specification |
| 348 | * is inappropriate for this key factory to produce a private key. |
| 349 | */ |
| 350 | public final PrivateKey generatePrivate(KeySpec keySpec) |
| 351 | throws InvalidKeySpecException { |
| 352 | if (serviceIterator == null) { |
| 353 | return spi.engineGeneratePrivate(keySpec); |
| 354 | } |
| 355 | Exception failure = null; |
| 356 | KeyFactorySpi mySpi = spi; |
| 357 | do { |
| 358 | try { |
| 359 | return mySpi.engineGeneratePrivate(keySpec); |
| 360 | } catch (Exception e) { |
| 361 | if (failure == null) { |
| 362 | failure = e; |
| 363 | } |
| 364 | mySpi = nextSpi(mySpi); |
| 365 | } |
| 366 | } while (mySpi != null); |
| 367 | if (failure instanceof RuntimeException) { |
| 368 | throw (RuntimeException)failure; |
| 369 | } |
| 370 | if (failure instanceof InvalidKeySpecException) { |
| 371 | throw (InvalidKeySpecException)failure; |
| 372 | } |
| 373 | throw new InvalidKeySpecException |
| 374 | ("Could not generate private key", failure); |
| 375 | } |
| 376 | |
| 377 | /** |
| 378 | * Returns a specification (key material) of the given key object. |
| 379 | * <code>keySpec</code> identifies the specification class in which |
| 380 | * the key material should be returned. It could, for example, be |
| 381 | * <code>DSAPublicKeySpec.class</code>, to indicate that the |
| 382 | * key material should be returned in an instance of the |
| 383 | * <code>DSAPublicKeySpec</code> class. |
| 384 | * |
| 385 | * @param key the key. |
| 386 | * |
| 387 | * @param keySpec the specification class in which |
| 388 | * the key material should be returned. |
| 389 | * |
| 390 | * @return the underlying key specification (key material) in an instance |
| 391 | * of the requested specification class. |
| 392 | * |
| 393 | * @exception InvalidKeySpecException if the requested key specification is |
| 394 | * inappropriate for the given key, or the given key cannot be processed |
| 395 | * (e.g., the given key has an unrecognized algorithm or format). |
| 396 | */ |
| 397 | public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec) |
| 398 | throws InvalidKeySpecException { |
| 399 | if (serviceIterator == null) { |
| 400 | return spi.engineGetKeySpec(key, keySpec); |
| 401 | } |
| 402 | Exception failure = null; |
| 403 | KeyFactorySpi mySpi = spi; |
| 404 | do { |
| 405 | try { |
| 406 | return mySpi.engineGetKeySpec(key, keySpec); |
| 407 | } catch (Exception e) { |
| 408 | if (failure == null) { |
| 409 | failure = e; |
| 410 | } |
| 411 | mySpi = nextSpi(mySpi); |
| 412 | } |
| 413 | } while (mySpi != null); |
| 414 | if (failure instanceof RuntimeException) { |
| 415 | throw (RuntimeException)failure; |
| 416 | } |
| 417 | if (failure instanceof InvalidKeySpecException) { |
| 418 | throw (InvalidKeySpecException)failure; |
| 419 | } |
| 420 | throw new InvalidKeySpecException |
| 421 | ("Could not get key spec", failure); |
| 422 | } |
| 423 | |
| 424 | /** |
| 425 | * Translates a key object, whose provider may be unknown or potentially |
| 426 | * untrusted, into a corresponding key object of this key factory. |
| 427 | * |
| 428 | * @param key the key whose provider is unknown or untrusted. |
| 429 | * |
| 430 | * @return the translated key. |
| 431 | * |
| 432 | * @exception InvalidKeyException if the given key cannot be processed |
| 433 | * by this key factory. |
| 434 | */ |
| 435 | public final Key translateKey(Key key) throws InvalidKeyException { |
| 436 | if (serviceIterator == null) { |
| 437 | return spi.engineTranslateKey(key); |
| 438 | } |
| 439 | Exception failure = null; |
| 440 | KeyFactorySpi mySpi = spi; |
| 441 | do { |
| 442 | try { |
| 443 | return mySpi.engineTranslateKey(key); |
| 444 | } catch (Exception e) { |
| 445 | if (failure == null) { |
| 446 | failure = e; |
| 447 | } |
| 448 | mySpi = nextSpi(mySpi); |
| 449 | } |
| 450 | } while (mySpi != null); |
| 451 | if (failure instanceof RuntimeException) { |
| 452 | throw (RuntimeException)failure; |
| 453 | } |
| 454 | if (failure instanceof InvalidKeyException) { |
| 455 | throw (InvalidKeyException)failure; |
| 456 | } |
| 457 | throw new InvalidKeyException |
| 458 | ("Could not translate key", failure); |
| 459 | } |
| 460 | |
| 461 | } |