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 | |
| 30 | import java.security.Provider.Service; |
| 31 | |
| 32 | import sun.security.jca.*; |
| 33 | import sun.security.jca.GetInstance.Instance; |
| 34 | |
| 35 | /** |
| 36 | * This class provides a cryptographically strong random number |
| 37 | * generator (RNG). |
| 38 | * |
| 39 | * <p>A cryptographically strong random number |
| 40 | * minimally complies with the statistical random number generator tests |
| 41 | * specified in <a href="http://csrc.nist.gov/cryptval/140-2.htm"> |
| 42 | * <i>FIPS 140-2, Security Requirements for Cryptographic Modules</i></a>, |
| 43 | * section 4.9.1. |
| 44 | * Additionally, SecureRandom must produce non-deterministic output. |
| 45 | * Therefore any seed material passed to a SecureRandom object must be |
| 46 | * unpredictable, and all SecureRandom output sequences must be |
| 47 | * cryptographically strong, as described in |
| 48 | * <a href="http://www.ietf.org/rfc/rfc1750.txt"> |
| 49 | * <i>RFC 1750: Randomness Recommendations for Security</i></a>. |
| 50 | * |
| 51 | * <p>A caller obtains a SecureRandom instance via the |
| 52 | * no-argument constructor or one of the <code>getInstance</code> methods: |
| 53 | * |
| 54 | * <pre> |
| 55 | * SecureRandom random = new SecureRandom(); |
| 56 | * </pre> |
| 57 | * |
| 58 | * <p> Many SecureRandom implementations are in the form of a pseudo-random |
| 59 | * number generator (PRNG), which means they use a deterministic algorithm |
| 60 | * to produce a pseudo-random sequence from a true random seed. |
| 61 | * Other implementations may produce true random numbers, |
| 62 | * and yet others may use a combination of both techniques. |
| 63 | * |
| 64 | * <p> Typical callers of SecureRandom invoke the following methods |
| 65 | * to retrieve random bytes: |
| 66 | * |
| 67 | * <pre> |
| 68 | * SecureRandom random = new SecureRandom(); |
| 69 | * byte bytes[] = new byte[20]; |
| 70 | * random.nextBytes(bytes); |
| 71 | * </pre> |
| 72 | * |
| 73 | * <p> Callers may also invoke the <code>generateSeed</code> method |
| 74 | * to generate a given number of seed bytes (to seed other random number |
| 75 | * generators, for example): |
| 76 | * <pre> |
| 77 | * byte seed[] = random.generateSeed(20); |
| 78 | * </pre> |
| 79 | * |
| 80 | * Note: Depending on the implementation, the <code>generateSeed</code> and |
| 81 | * <code>nextBytes</code> methods may block as entropy is being gathered, |
| 82 | * for example, if they need to read from /dev/random on various unix-like |
| 83 | * operating systems. |
| 84 | * |
| 85 | * @see java.security.SecureRandomSpi |
| 86 | * @see java.util.Random |
| 87 | * |
| 88 | * @author Benjamin Renaud |
| 89 | * @author Josh Bloch |
| 90 | */ |
| 91 | |
| 92 | public class SecureRandom extends java.util.Random { |
| 93 | |
| 94 | /** |
| 95 | * The provider. |
| 96 | * |
| 97 | * @serial |
| 98 | * @since 1.2 |
| 99 | */ |
| 100 | private Provider provider = null; |
| 101 | |
| 102 | /** |
| 103 | * The provider implementation. |
| 104 | * |
| 105 | * @serial |
| 106 | * @since 1.2 |
| 107 | */ |
| 108 | private SecureRandomSpi secureRandomSpi = null; |
| 109 | |
| 110 | /* |
| 111 | * The algorithm name of null if unknown. |
| 112 | * |
| 113 | * @serial |
| 114 | * @since 1.5 |
| 115 | */ |
| 116 | private String algorithm; |
| 117 | |
| 118 | // Seed Generator |
| 119 | private static volatile SecureRandom seedGenerator = null; |
| 120 | |
| 121 | /** |
| 122 | * Constructs a secure random number generator (RNG) implementing the |
| 123 | * default random number algorithm. |
| 124 | * |
| 125 | * <p> This constructor traverses the list of registered security Providers, |
| 126 | * starting with the most preferred Provider. |
| 127 | * A new SecureRandom object encapsulating the |
| 128 | * SecureRandomSpi implementation from the first |
| 129 | * Provider that supports a SecureRandom (RNG) algorithm is returned. |
| 130 | * If none of the Providers support a RNG algorithm, |
| 131 | * then an implementation-specific default is returned. |
| 132 | * |
| 133 | * <p> Note that the list of registered providers may be retrieved via |
| 134 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 135 | * |
| 136 | * <p> See Appendix A in the <a href= |
| 137 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 138 | * Java Cryptography Architecture API Specification & Reference </a> |
| 139 | * for information about standard RNG algorithm names. |
| 140 | * |
| 141 | * <p> The returned SecureRandom object has not been seeded. To seed the |
| 142 | * returned object, call the <code>setSeed</code> method. |
| 143 | * If <code>setSeed</code> is not called, the first call to |
| 144 | * <code>nextBytes</code> will force the SecureRandom object to seed itself. |
| 145 | * This self-seeding will not occur if <code>setSeed</code> was |
| 146 | * previously called. |
| 147 | */ |
| 148 | public SecureRandom() { |
| 149 | /* |
| 150 | * This call to our superclass constructor will result in a call |
| 151 | * to our own <code>setSeed</code> method, which will return |
| 152 | * immediately when it is passed zero. |
| 153 | */ |
| 154 | super(0); |
| 155 | getDefaultPRNG(false, null); |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * Constructs a secure random number generator (RNG) implementing the |
| 160 | * default random number algorithm. |
| 161 | * The SecureRandom instance is seeded with the specified seed bytes. |
| 162 | * |
| 163 | * <p> This constructor traverses the list of registered security Providers, |
| 164 | * starting with the most preferred Provider. |
| 165 | * A new SecureRandom object encapsulating the |
| 166 | * SecureRandomSpi implementation from the first |
| 167 | * Provider that supports a SecureRandom (RNG) algorithm is returned. |
| 168 | * If none of the Providers support a RNG algorithm, |
| 169 | * then an implementation-specific default is returned. |
| 170 | * |
| 171 | * <p> Note that the list of registered providers may be retrieved via |
| 172 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 173 | * |
| 174 | * <p> See Appendix A in the <a href= |
| 175 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 176 | * Java Cryptography Architecture API Specification & Reference </a> |
| 177 | * for information about standard RNG algorithm names. |
| 178 | * |
| 179 | * @param seed the seed. |
| 180 | */ |
| 181 | public SecureRandom(byte seed[]) { |
| 182 | super(0); |
| 183 | getDefaultPRNG(true, seed); |
| 184 | } |
| 185 | |
| 186 | private void getDefaultPRNG(boolean setSeed, byte[] seed) { |
| 187 | String prng = getPrngAlgorithm(); |
| 188 | if (prng == null) { |
| 189 | // bummer, get the SUN implementation |
| 190 | prng = "SHA1PRNG"; |
| 191 | this.secureRandomSpi = new sun.security.provider.SecureRandom(); |
| 192 | this.provider = Providers.getSunProvider(); |
| 193 | if (setSeed) { |
| 194 | this.secureRandomSpi.engineSetSeed(seed); |
| 195 | } |
| 196 | } else { |
| 197 | try { |
| 198 | SecureRandom random = SecureRandom.getInstance(prng); |
| 199 | this.secureRandomSpi = random.getSecureRandomSpi(); |
| 200 | this.provider = random.getProvider(); |
| 201 | if (setSeed) { |
| 202 | this.secureRandomSpi.engineSetSeed(seed); |
| 203 | } |
| 204 | } catch (NoSuchAlgorithmException nsae) { |
| 205 | // never happens, because we made sure the algorithm exists |
| 206 | throw new RuntimeException(nsae); |
| 207 | } |
| 208 | } |
| 209 | // JDK 1.1 based implementations subclass SecureRandom instead of |
| 210 | // SecureRandomSpi. They will also go through this code path because |
| 211 | // they must call a SecureRandom constructor as it is their superclass. |
| 212 | // If we are dealing with such an implementation, do not set the |
| 213 | // algorithm value as it would be inaccurate. |
| 214 | if (getClass() == SecureRandom.class) { |
| 215 | this.algorithm = prng; |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * Creates a SecureRandom object. |
| 221 | * |
| 222 | * @param secureRandomSpi the SecureRandom implementation. |
| 223 | * @param provider the provider. |
| 224 | */ |
| 225 | protected SecureRandom(SecureRandomSpi secureRandomSpi, |
| 226 | Provider provider) { |
| 227 | this(secureRandomSpi, provider, null); |
| 228 | } |
| 229 | |
| 230 | private SecureRandom(SecureRandomSpi secureRandomSpi, Provider provider, |
| 231 | String algorithm) { |
| 232 | super(0); |
| 233 | this.secureRandomSpi = secureRandomSpi; |
| 234 | this.provider = provider; |
| 235 | this.algorithm = algorithm; |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * Returns a SecureRandom object that implements the specified |
| 240 | * Random Number Generator (RNG) algorithm. |
| 241 | * |
| 242 | * <p> This method traverses the list of registered security Providers, |
| 243 | * starting with the most preferred Provider. |
| 244 | * A new SecureRandom object encapsulating the |
| 245 | * SecureRandomSpi implementation from the first |
| 246 | * Provider that supports the specified algorithm is returned. |
| 247 | * |
| 248 | * <p> Note that the list of registered providers may be retrieved via |
| 249 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 250 | * |
| 251 | * <p> The returned SecureRandom object has not been seeded. To seed the |
| 252 | * returned object, call the <code>setSeed</code> method. |
| 253 | * If <code>setSeed</code> is not called, the first call to |
| 254 | * <code>nextBytes</code> will force the SecureRandom object to seed itself. |
| 255 | * This self-seeding will not occur if <code>setSeed</code> was |
| 256 | * previously called. |
| 257 | * |
| 258 | * @param algorithm the name of the RNG algorithm. |
| 259 | * See Appendix A in the <a href= |
| 260 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 261 | * Java Cryptography Architecture API Specification & Reference </a> |
| 262 | * for information about standard RNG algorithm names. |
| 263 | * |
| 264 | * @return the new SecureRandom object. |
| 265 | * |
| 266 | * @exception NoSuchAlgorithmException if no Provider supports a |
| 267 | * SecureRandomSpi implementation for the |
| 268 | * specified algorithm. |
| 269 | * |
| 270 | * @see Provider |
| 271 | * |
| 272 | * @since 1.2 |
| 273 | */ |
| 274 | public static SecureRandom getInstance(String algorithm) |
| 275 | throws NoSuchAlgorithmException { |
| 276 | Instance instance = GetInstance.getInstance("SecureRandom", |
| 277 | SecureRandomSpi.class, algorithm); |
| 278 | return new SecureRandom((SecureRandomSpi)instance.impl, |
| 279 | instance.provider, algorithm); |
| 280 | } |
| 281 | |
| 282 | /** |
| 283 | * Returns a SecureRandom object that implements the specified |
| 284 | * Random Number Generator (RNG) algorithm. |
| 285 | * |
| 286 | * <p> A new SecureRandom object encapsulating the |
| 287 | * SecureRandomSpi implementation from the specified provider |
| 288 | * is returned. The specified provider must be registered |
| 289 | * in the security provider list. |
| 290 | * |
| 291 | * <p> Note that the list of registered providers may be retrieved via |
| 292 | * the {@link Security#getProviders() Security.getProviders()} method. |
| 293 | * |
| 294 | * <p> The returned SecureRandom object has not been seeded. To seed the |
| 295 | * returned object, call the <code>setSeed</code> method. |
| 296 | * If <code>setSeed</code> is not called, the first call to |
| 297 | * <code>nextBytes</code> will force the SecureRandom object to seed itself. |
| 298 | * This self-seeding will not occur if <code>setSeed</code> was |
| 299 | * previously called. |
| 300 | * |
| 301 | * @param algorithm the name of the RNG algorithm. |
| 302 | * See Appendix A in the <a href= |
| 303 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 304 | * Java Cryptography Architecture API Specification & Reference </a> |
| 305 | * for information about standard RNG algorithm names. |
| 306 | * |
| 307 | * @param provider the name of the provider. |
| 308 | * |
| 309 | * @return the new SecureRandom object. |
| 310 | * |
| 311 | * @exception NoSuchAlgorithmException if a SecureRandomSpi |
| 312 | * implementation for the specified algorithm is not |
| 313 | * available from the specified provider. |
| 314 | * |
| 315 | * @exception NoSuchProviderException if the specified provider is not |
| 316 | * registered in the security provider list. |
| 317 | * |
| 318 | * @exception IllegalArgumentException if the provider name is null |
| 319 | * or empty. |
| 320 | * |
| 321 | * @see Provider |
| 322 | * |
| 323 | * @since 1.2 |
| 324 | */ |
| 325 | public static SecureRandom getInstance(String algorithm, String provider) |
| 326 | throws NoSuchAlgorithmException, NoSuchProviderException { |
| 327 | Instance instance = GetInstance.getInstance("SecureRandom", |
| 328 | SecureRandomSpi.class, algorithm, provider); |
| 329 | return new SecureRandom((SecureRandomSpi)instance.impl, |
| 330 | instance.provider, algorithm); |
| 331 | } |
| 332 | |
| 333 | /** |
| 334 | * Returns a SecureRandom object that implements the specified |
| 335 | * Random Number Generator (RNG) algorithm. |
| 336 | * |
| 337 | * <p> A new SecureRandom object encapsulating the |
| 338 | * SecureRandomSpi implementation from the specified Provider |
| 339 | * object is returned. Note that the specified Provider object |
| 340 | * does not have to be registered in the provider list. |
| 341 | * |
| 342 | * <p> The returned SecureRandom object has not been seeded. To seed the |
| 343 | * returned object, call the <code>setSeed</code> method. |
| 344 | * If <code>setSeed</code> is not called, the first call to |
| 345 | * <code>nextBytes</code> will force the SecureRandom object to seed itself. |
| 346 | * This self-seeding will not occur if <code>setSeed</code> was |
| 347 | * previously called. |
| 348 | * |
| 349 | * @param algorithm the name of the RNG algorithm. |
| 350 | * See Appendix A in the <a href= |
| 351 | * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA"> |
| 352 | * Java Cryptography Architecture API Specification & Reference </a> |
| 353 | * for information about standard RNG algorithm names. |
| 354 | * |
| 355 | * @param provider the provider. |
| 356 | * |
| 357 | * @return the new SecureRandom object. |
| 358 | * |
| 359 | * @exception NoSuchAlgorithmException if a SecureRandomSpi |
| 360 | * implementation for the specified algorithm is not available |
| 361 | * from the specified Provider object. |
| 362 | * |
| 363 | * @exception IllegalArgumentException if the specified provider is null. |
| 364 | * |
| 365 | * @see Provider |
| 366 | * |
| 367 | * @since 1.4 |
| 368 | */ |
| 369 | public static SecureRandom getInstance(String algorithm, |
| 370 | Provider provider) throws NoSuchAlgorithmException { |
| 371 | Instance instance = GetInstance.getInstance("SecureRandom", |
| 372 | SecureRandomSpi.class, algorithm, provider); |
| 373 | return new SecureRandom((SecureRandomSpi)instance.impl, |
| 374 | instance.provider, algorithm); |
| 375 | } |
| 376 | |
| 377 | /** |
| 378 | * Returns the SecureRandomSpi of this SecureRandom object. |
| 379 | */ |
| 380 | SecureRandomSpi getSecureRandomSpi() { |
| 381 | return secureRandomSpi; |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * Returns the provider of this SecureRandom object. |
| 386 | * |
| 387 | * @return the provider of this SecureRandom object. |
| 388 | */ |
| 389 | public final Provider getProvider() { |
| 390 | return provider; |
| 391 | } |
| 392 | |
| 393 | /** |
| 394 | * Returns the name of the algorithm implemented by this SecureRandom |
| 395 | * object. |
| 396 | * |
| 397 | * @return the name of the algorithm or <code>unknown</code> |
| 398 | * if the algorithm name cannot be determined. |
| 399 | * @since 1.5 |
| 400 | */ |
| 401 | public String getAlgorithm() { |
| 402 | return (algorithm != null) ? algorithm : "unknown"; |
| 403 | } |
| 404 | |
| 405 | /** |
| 406 | * Reseeds this random object. The given seed supplements, rather than |
| 407 | * replaces, the existing seed. Thus, repeated calls are guaranteed |
| 408 | * never to reduce randomness. |
| 409 | * |
| 410 | * @param seed the seed. |
| 411 | * |
| 412 | * @see #getSeed |
| 413 | */ |
| 414 | synchronized public void setSeed(byte[] seed) { |
| 415 | secureRandomSpi.engineSetSeed(seed); |
| 416 | } |
| 417 | |
| 418 | /** |
| 419 | * Reseeds this random object, using the eight bytes contained |
| 420 | * in the given <code>long seed</code>. The given seed supplements, |
| 421 | * rather than replaces, the existing seed. Thus, repeated calls |
| 422 | * are guaranteed never to reduce randomness. |
| 423 | * |
| 424 | * <p>This method is defined for compatibility with |
| 425 | * <code>java.util.Random</code>. |
| 426 | * |
| 427 | * @param seed the seed. |
| 428 | * |
| 429 | * @see #getSeed |
| 430 | */ |
| 431 | public void setSeed(long seed) { |
| 432 | /* |
| 433 | * Ignore call from super constructor (as well as any other calls |
| 434 | * unfortunate enough to be passing 0). It's critical that we |
| 435 | * ignore call from superclass constructor, as digest has not |
| 436 | * yet been initialized at that point. |
| 437 | */ |
| 438 | if (seed != 0) { |
| 439 | secureRandomSpi.engineSetSeed(longToByteArray(seed)); |
| 440 | } |
| 441 | } |
| 442 | |
| 443 | /** |
| 444 | * Generates a user-specified number of random bytes. |
| 445 | * |
| 446 | * <p> If a call to <code>setSeed</code> had not occurred previously, |
| 447 | * the first call to this method forces this SecureRandom object |
| 448 | * to seed itself. This self-seeding will not occur if |
| 449 | * <code>setSeed</code> was previously called. |
| 450 | * |
| 451 | * @param bytes the array to be filled in with random bytes. |
| 452 | */ |
| 453 | |
| 454 | synchronized public void nextBytes(byte[] bytes) { |
| 455 | secureRandomSpi.engineNextBytes(bytes); |
| 456 | } |
| 457 | |
| 458 | /** |
| 459 | * Generates an integer containing the user-specified number of |
| 460 | * pseudo-random bits (right justified, with leading zeros). This |
| 461 | * method overrides a <code>java.util.Random</code> method, and serves |
| 462 | * to provide a source of random bits to all of the methods inherited |
| 463 | * from that class (for example, <code>nextInt</code>, |
| 464 | * <code>nextLong</code>, and <code>nextFloat</code>). |
| 465 | * |
| 466 | * @param numBits number of pseudo-random bits to be generated, where |
| 467 | * 0 <= <code>numBits</code> <= 32. |
| 468 | * |
| 469 | * @return an <code>int</code> containing the user-specified number |
| 470 | * of pseudo-random bits (right justified, with leading zeros). |
| 471 | */ |
| 472 | final protected int next(int numBits) { |
| 473 | int numBytes = (numBits+7)/8; |
| 474 | byte b[] = new byte[numBytes]; |
| 475 | int next = 0; |
| 476 | |
| 477 | nextBytes(b); |
| 478 | for (int i = 0; i < numBytes; i++) |
| 479 | next = (next << 8) + (b[i] & 0xFF); |
| 480 | |
| 481 | return next >>> (numBytes*8 - numBits); |
| 482 | } |
| 483 | |
| 484 | /** |
| 485 | * Returns the given number of seed bytes, computed using the seed |
| 486 | * generation algorithm that this class uses to seed itself. This |
| 487 | * call may be used to seed other random number generators. |
| 488 | * |
| 489 | * <p>This method is only included for backwards compatibility. |
| 490 | * The caller is encouraged to use one of the alternative |
| 491 | * <code>getInstance</code> methods to obtain a SecureRandom object, and |
| 492 | * then call the <code>generateSeed</code> method to obtain seed bytes |
| 493 | * from that object. |
| 494 | * |
| 495 | * @param numBytes the number of seed bytes to generate. |
| 496 | * |
| 497 | * @return the seed bytes. |
| 498 | * |
| 499 | * @see #setSeed |
| 500 | */ |
| 501 | public static byte[] getSeed(int numBytes) { |
| 502 | if (seedGenerator == null) |
| 503 | seedGenerator = new SecureRandom(); |
| 504 | return seedGenerator.generateSeed(numBytes); |
| 505 | } |
| 506 | |
| 507 | /** |
| 508 | * Returns the given number of seed bytes, computed using the seed |
| 509 | * generation algorithm that this class uses to seed itself. This |
| 510 | * call may be used to seed other random number generators. |
| 511 | * |
| 512 | * @param numBytes the number of seed bytes to generate. |
| 513 | * |
| 514 | * @return the seed bytes. |
| 515 | */ |
| 516 | public byte[] generateSeed(int numBytes) { |
| 517 | return secureRandomSpi.engineGenerateSeed(numBytes); |
| 518 | } |
| 519 | |
| 520 | /** |
| 521 | * Helper function to convert a long into a byte array (least significant |
| 522 | * byte first). |
| 523 | */ |
| 524 | private static byte[] longToByteArray(long l) { |
| 525 | byte[] retVal = new byte[8]; |
| 526 | |
| 527 | for (int i = 0; i < 8; i++) { |
| 528 | retVal[i] = (byte) l; |
| 529 | l >>= 8; |
| 530 | } |
| 531 | |
| 532 | return retVal; |
| 533 | } |
| 534 | |
| 535 | /** |
| 536 | * Gets a default PRNG algorithm by looking through all registered |
| 537 | * providers. Returns the first PRNG algorithm of the first provider that |
| 538 | * has registered a SecureRandom implementation, or null if none of the |
| 539 | * registered providers supplies a SecureRandom implementation. |
| 540 | */ |
| 541 | private static String getPrngAlgorithm() { |
| 542 | for (Provider p : Providers.getProviderList().providers()) { |
| 543 | for (Service s : p.getServices()) { |
| 544 | if (s.getType().equals("SecureRandom")) { |
| 545 | return s.getAlgorithm(); |
| 546 | } |
| 547 | } |
| 548 | } |
| 549 | return null; |
| 550 | } |
| 551 | |
| 552 | // Declare serialVersionUID to be compatible with JDK1.1 |
| 553 | static final long serialVersionUID = 4940670005562187L; |
| 554 | |
| 555 | // Retain unused values serialized from JDK1.1 |
| 556 | /** |
| 557 | * @serial |
| 558 | */ |
| 559 | private byte[] state; |
| 560 | /** |
| 561 | * @serial |
| 562 | */ |
| 563 | private MessageDigest digest = null; |
| 564 | /** |
| 565 | * @serial |
| 566 | * |
| 567 | * We know that the MessageDigest class does not implement |
| 568 | * java.io.Serializable. However, since this field is no longer |
| 569 | * used, it will always be NULL and won't affect the serialization |
| 570 | * of the SecureRandom class itself. |
| 571 | */ |
| 572 | private byte[] randomBytes; |
| 573 | /** |
| 574 | * @serial |
| 575 | */ |
| 576 | private int randomBytesUsed; |
| 577 | /** |
| 578 | * @serial |
| 579 | */ |
| 580 | private long counter; |
| 581 | } |