J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.crypto; |
| 27 | |
| 28 | import java.util.*; |
| 29 | |
| 30 | import java.security.*; |
| 31 | import java.security.Provider.Service; |
| 32 | import java.security.spec.*; |
| 33 | |
| 34 | import sun.security.jca.*; |
| 35 | import sun.security.jca.GetInstance.Instance; |
| 36 | |
| 37 | /** |
| 38 | * This class represents a factory for secret keys. |
| 39 | * |
| 40 | * <P> Key factories are used to convert <I>keys</I> (opaque |
| 41 | * cryptographic keys of type <code>Key</code>) into <I>key specifications</I> |
| 42 | * (transparent representations of the underlying key material), and vice |
| 43 | * versa. |
| 44 | * Secret key factories operate only on secret (symmetric) keys. |
| 45 | * |
| 46 | * <P> Key factories are bi-directional, i.e., they allow to build an opaque |
| 47 | * key object from a given key specification (key material), or to retrieve |
| 48 | * the underlying key material of a key object in a suitable format. |
| 49 | * |
| 50 | * <P> Application developers should refer to their provider's documentation |
| 51 | * to find out which key specifications are supported by the |
| 52 | * {@link #generateSecret(java.security.spec.KeySpec) generateSecret} and |
| 53 | * {@link #getKeySpec(javax.crypto.SecretKey, java.lang.Class) getKeySpec} |
| 54 | * methods. |
| 55 | * For example, the DES secret-key factory supplied by the "SunJCE" provider |
| 56 | * supports <code>DESKeySpec</code> as a transparent representation of DES |
| 57 | * keys, and that provider's secret-key factory for Triple DES keys supports |
| 58 | * <code>DESedeKeySpec</code> as a transparent representation of Triple DES |
| 59 | * keys. |
| 60 | * |
| 61 | * @author Jan Luehe |
| 62 | * |
| 63 | * @see SecretKey |
| 64 | * @see javax.crypto.spec.DESKeySpec |
| 65 | * @see javax.crypto.spec.DESedeKeySpec |
| 66 | * @see javax.crypto.spec.PBEKeySpec |
| 67 | * @since 1.4 |
| 68 | */ |
| 69 | |
| 70 | public class SecretKeyFactory { |
| 71 | |
| 72 | // The provider |
| 73 | private Provider provider; |
| 74 | |
| 75 | // The algorithm associated with this factory |
| 76 | private final String algorithm; |
| 77 | |
| 78 | // The provider implementation (delegate) |
| 79 | private volatile SecretKeyFactorySpi spi; |
| 80 | |
| 81 | // lock for mutex during provider selection |
| 82 | private final Object lock = new Object(); |
| 83 | |
| 84 | // remaining services to try in provider selection |
| 85 | // null once provider is selected |
| 86 | private Iterator serviceIterator; |
| 87 | |
| 88 | /** |
| 89 | * Creates a SecretKeyFactory object. |
| 90 | * |
| 91 | * @param keyFacSpi the delegate |
| 92 | * @param provider the provider |
| 93 | * @param algorithm the secret-key algorithm |
| 94 | */ |
| 95 | protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, |
| 96 | Provider provider, String algorithm) { |
| 97 | this.spi = keyFacSpi; |
| 98 | this.provider = provider; |
| 99 | this.algorithm = algorithm; |
| 100 | } |
| 101 | |
| 102 | private SecretKeyFactory(String algorithm) throws NoSuchAlgorithmException { |
| 103 | this.algorithm = algorithm; |
| 104 | List list = GetInstance.getServices("SecretKeyFactory", algorithm); |
| 105 | serviceIterator = list.iterator(); |
| 106 | // fetch and instantiate initial spi |
| 107 | if (nextSpi(null) == null) { |
| 108 | throw new NoSuchAlgorithmException |
| 109 | (algorithm + " SecretKeyFactory not available"); |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Returns a <code>SecretKeyFactory</code> object that converts |
| 115 | * secret keys of the specified algorithm. |
| 116 | * |
| 117 | * <p> This method traverses the list of registered security Providers, |
| 118 | * starting with the most preferred Provider. |
| 119 | * A new SecretKeyFactory object encapsulating the |
| 120 | * SecretKeyFactorySpi implementation from the first |
| 121 | * Provider that supports the specified algorithm is returned. |
| 122 | * |
| 123 | * <p> Note that the list of registered providers may be retrieved via |
| 124 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 125 | * |
| 126 | * @param algorithm the standard name of the requested secret-key |
| 127 | * algorithm. |
| 128 | * See Appendix A in the <a href= |
| 129 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 130 | * Java Cryptography Architecture Reference Guide</a> |
| 131 | * for information about standard algorithm names. |
| 132 | * |
| 133 | * @return the new <code>SecretKeyFactory</code> object. |
| 134 | * |
| 135 | * @exception NullPointerException if the specified algorithm |
| 136 | * is null. |
| 137 | * |
| 138 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 139 | * SecretKeyFactorySpi implementation for the |
| 140 | * specified algorithm. |
| 141 | * |
| 142 | * @see java.security.Provider |
| 143 | */ |
| 144 | public static final SecretKeyFactory getInstance(String algorithm) |
| 145 | throws NoSuchAlgorithmException { |
| 146 | return new SecretKeyFactory(algorithm); |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * Returns a <code>SecretKeyFactory</code> object that converts |
| 151 | * secret keys of the specified algorithm. |
| 152 | * |
| 153 | * <p> A new SecretKeyFactory object encapsulating the |
| 154 | * SecretKeyFactorySpi implementation from the specified provider |
| 155 | * is returned. The specified provider must be registered |
| 156 | * in the security provider list. |
| 157 | * |
| 158 | * <p> Note that the list of registered providers may be retrieved via |
| 159 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 160 | * |
| 161 | * @param algorithm the standard name of the requested secret-key |
| 162 | * algorithm. |
| 163 | * See Appendix A in the <a href= |
| 164 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 165 | * Java Cryptography Architecture Reference Guide</a> |
| 166 | * for information about standard algorithm names. |
| 167 | * |
| 168 | * @param provider the name of the provider. |
| 169 | * |
| 170 | * @return the new <code>SecretKeyFactory</code> object. |
| 171 | * |
| 172 | * @exception NoSuchAlgorithmException if a SecretKeyFactorySpi |
| 173 | * implementation for the specified algorithm is not |
| 174 | * available from the specified provider. |
| 175 | * |
| 176 | * @exception NullPointerException if the specified algorithm |
| 177 | * is null. |
| 178 | * |
| 179 | * @throws NoSuchProviderException if the specified provider is not |
| 180 | * registered in the security provider list. |
| 181 | * |
| 182 | * @exception IllegalArgumentException if the <code>provider</code> |
| 183 | * is null or empty. |
| 184 | * |
| 185 | * @see java.security.Provider |
| 186 | */ |
| 187 | public static final SecretKeyFactory getInstance(String algorithm, |
| 188 | String provider) throws NoSuchAlgorithmException, |
| 189 | NoSuchProviderException { |
| 190 | Instance instance = JceSecurity.getInstance("SecretKeyFactory", |
| 191 | SecretKeyFactorySpi.class, algorithm, provider); |
| 192 | return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl, |
| 193 | instance.provider, algorithm); |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Returns a <code>SecretKeyFactory</code> object that converts |
| 198 | * secret keys of the specified algorithm. |
| 199 | * |
| 200 | * <p> A new SecretKeyFactory object encapsulating the |
| 201 | * SecretKeyFactorySpi implementation from the specified Provider |
| 202 | * object is returned. Note that the specified Provider object |
| 203 | * does not have to be registered in the provider list. |
| 204 | * |
| 205 | * @param algorithm the standard name of the requested secret-key |
| 206 | * algorithm. |
| 207 | * See Appendix A in the <a href= |
| 208 | * "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 209 | * Java Cryptography Architecture Reference Guide</a> |
| 210 | * for information about standard algorithm names. |
| 211 | * |
| 212 | * @param provider the provider. |
| 213 | * |
| 214 | * @return the new <code>SecretKeyFactory</code> object. |
| 215 | * |
| 216 | * @exception NullPointerException if the specified algorithm |
| 217 | * is null. |
| 218 | * |
| 219 | * @exception NoSuchAlgorithmException if a SecretKeyFactorySpi |
| 220 | * implementation for the specified algorithm is not available |
| 221 | * from the specified Provider object. |
| 222 | * |
| 223 | * @exception IllegalArgumentException if the <code>provider</code> |
| 224 | * is null. |
| 225 | * |
| 226 | * @see java.security.Provider |
| 227 | */ |
| 228 | public static final SecretKeyFactory getInstance(String algorithm, |
| 229 | Provider provider) throws NoSuchAlgorithmException { |
| 230 | Instance instance = JceSecurity.getInstance("SecretKeyFactory", |
| 231 | SecretKeyFactorySpi.class, algorithm, provider); |
| 232 | return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl, |
| 233 | instance.provider, algorithm); |
| 234 | } |
| 235 | |
| 236 | /** |
| 237 | * Returns the provider of this <code>SecretKeyFactory</code> object. |
| 238 | * |
| 239 | * @return the provider of this <code>SecretKeyFactory</code> object |
| 240 | */ |
| 241 | public final Provider getProvider() { |
| 242 | synchronized (lock) { |
| 243 | // disable further failover after this call |
| 244 | serviceIterator = null; |
| 245 | return provider; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /** |
| 250 | * Returns the algorithm name of this <code>SecretKeyFactory</code> object. |
| 251 | * |
| 252 | * <p>This is the same name that was specified in one of the |
| 253 | * <code>getInstance</code> calls that created this |
| 254 | * <code>SecretKeyFactory</code> object. |
| 255 | * |
| 256 | * @return the algorithm name of this <code>SecretKeyFactory</code> |
| 257 | * object. |
| 258 | */ |
| 259 | public final String getAlgorithm() { |
| 260 | return this.algorithm; |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * Update the active spi of this class and return the next |
| 265 | * implementation for failover. If no more implemenations are |
| 266 | * available, this method returns null. However, the active spi of |
| 267 | * this class is never set to null. |
| 268 | */ |
| 269 | private SecretKeyFactorySpi nextSpi(SecretKeyFactorySpi oldSpi) { |
| 270 | synchronized (lock) { |
| 271 | // somebody else did a failover concurrently |
| 272 | // try that spi now |
| 273 | if ((oldSpi != null) && (oldSpi != spi)) { |
| 274 | return spi; |
| 275 | } |
| 276 | if (serviceIterator == null) { |
| 277 | return null; |
| 278 | } |
| 279 | while (serviceIterator.hasNext()) { |
| 280 | Service s = (Service)serviceIterator.next(); |
| 281 | if (JceSecurity.canUseProvider(s.getProvider()) == false) { |
| 282 | continue; |
| 283 | } |
| 284 | try { |
| 285 | Object obj = s.newInstance(null); |
| 286 | if (obj instanceof SecretKeyFactorySpi == false) { |
| 287 | continue; |
| 288 | } |
| 289 | SecretKeyFactorySpi spi = (SecretKeyFactorySpi)obj; |
| 290 | provider = s.getProvider(); |
| 291 | this.spi = spi; |
| 292 | return spi; |
| 293 | } catch (NoSuchAlgorithmException e) { |
| 294 | // ignore |
| 295 | } |
| 296 | } |
| 297 | serviceIterator = null; |
| 298 | return null; |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Generates a <code>SecretKey</code> object from the provided key |
| 304 | * specification (key material). |
| 305 | * |
| 306 | * @param keySpec the specification (key material) of the secret key |
| 307 | * |
| 308 | * @return the secret key |
| 309 | * |
| 310 | * @exception InvalidKeySpecException if the given key specification |
| 311 | * is inappropriate for this secret-key factory to produce a secret key. |
| 312 | */ |
| 313 | public final SecretKey generateSecret(KeySpec keySpec) |
| 314 | throws InvalidKeySpecException { |
| 315 | if (serviceIterator == null) { |
| 316 | return spi.engineGenerateSecret(keySpec); |
| 317 | } |
| 318 | Exception failure = null; |
| 319 | SecretKeyFactorySpi mySpi = spi; |
| 320 | do { |
| 321 | try { |
| 322 | return mySpi.engineGenerateSecret(keySpec); |
| 323 | } catch (Exception e) { |
| 324 | if (failure == null) { |
| 325 | failure = e; |
| 326 | } |
| 327 | mySpi = nextSpi(mySpi); |
| 328 | } |
| 329 | } while (mySpi != null); |
| 330 | if (failure instanceof InvalidKeySpecException) { |
| 331 | throw (InvalidKeySpecException)failure; |
| 332 | } |
| 333 | throw new InvalidKeySpecException |
| 334 | ("Could not generate secret key", failure); |
| 335 | } |
| 336 | |
| 337 | /** |
| 338 | * Returns a specification (key material) of the given key object |
| 339 | * in the requested format. |
| 340 | * |
| 341 | * @param key the key |
| 342 | * @param keySpec the requested format in which the key material shall be |
| 343 | * returned |
| 344 | * |
| 345 | * @return the underlying key specification (key material) in the |
| 346 | * requested format |
| 347 | * |
| 348 | * @exception InvalidKeySpecException if the requested key specification is |
| 349 | * inappropriate for the given key (e.g., the algorithms associated with |
| 350 | * <code>key</code> and <code>keySpec</code> do not match, or |
| 351 | * <code>key</code> references a key on a cryptographic hardware device |
| 352 | * whereas <code>keySpec</code> is the specification of a software-based |
| 353 | * key), or the given key cannot be dealt with |
| 354 | * (e.g., the given key has an algorithm or format not supported by this |
| 355 | * secret-key factory). |
| 356 | */ |
| 357 | public final KeySpec getKeySpec(SecretKey key, Class keySpec) |
| 358 | throws InvalidKeySpecException { |
| 359 | if (serviceIterator == null) { |
| 360 | return spi.engineGetKeySpec(key, keySpec); |
| 361 | } |
| 362 | Exception failure = null; |
| 363 | SecretKeyFactorySpi mySpi = spi; |
| 364 | do { |
| 365 | try { |
| 366 | return mySpi.engineGetKeySpec(key, keySpec); |
| 367 | } catch (Exception e) { |
| 368 | if (failure == null) { |
| 369 | failure = e; |
| 370 | } |
| 371 | mySpi = nextSpi(mySpi); |
| 372 | } |
| 373 | } while (mySpi != null); |
| 374 | if (failure instanceof InvalidKeySpecException) { |
| 375 | throw (InvalidKeySpecException)failure; |
| 376 | } |
| 377 | throw new InvalidKeySpecException |
| 378 | ("Could not get key spec", failure); |
| 379 | } |
| 380 | |
| 381 | /** |
| 382 | * Translates a key object, whose provider may be unknown or potentially |
| 383 | * untrusted, into a corresponding key object of this secret-key factory. |
| 384 | * |
| 385 | * @param key the key whose provider is unknown or untrusted |
| 386 | * |
| 387 | * @return the translated key |
| 388 | * |
| 389 | * @exception InvalidKeyException if the given key cannot be processed |
| 390 | * by this secret-key factory. |
| 391 | */ |
| 392 | public final SecretKey translateKey(SecretKey key) |
| 393 | throws InvalidKeyException { |
| 394 | if (serviceIterator == null) { |
| 395 | return spi.engineTranslateKey(key); |
| 396 | } |
| 397 | Exception failure = null; |
| 398 | SecretKeyFactorySpi mySpi = spi; |
| 399 | do { |
| 400 | try { |
| 401 | return mySpi.engineTranslateKey(key); |
| 402 | } catch (Exception e) { |
| 403 | if (failure == null) { |
| 404 | failure = e; |
| 405 | } |
| 406 | mySpi = nextSpi(mySpi); |
| 407 | } |
| 408 | } while (mySpi != null); |
| 409 | if (failure instanceof InvalidKeyException) { |
| 410 | throw (InvalidKeyException)failure; |
| 411 | } |
| 412 | throw new InvalidKeyException |
| 413 | ("Could not translate key", failure); |
| 414 | } |
| 415 | } |