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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 java.security; | ||
| 27 | |||
| 28 | import java.security.spec.AlgorithmParameterSpec; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * The <code>AlgorithmParameterGenerator</code> class is used to generate a | ||
| 32 | * set of | ||
| 33 | * parameters to be used with a certain algorithm. Parameter generators | ||
| 34 | * are constructed using the <code>getInstance</code> factory methods | ||
| 35 | * (static methods that return instances of a given class). | ||
| 36 | * | ||
| 37 | * <P>The object that will generate the parameters can be initialized | ||
| 38 | * in two different ways: in an algorithm-independent manner, or in an | ||
| 39 | * algorithm-specific manner: | ||
| 40 | * | ||
| 41 | * <ul> | ||
| 42 | * <li>The algorithm-independent approach uses the fact that all parameter | ||
| 43 | * generators share the concept of a "size" and a | ||
| 44 | * source of randomness. The measure of size is universally shared | ||
| 45 | * by all algorithm parameters, though it is interpreted differently | ||
| 46 | * for different algorithms. For example, in the case of parameters for | ||
| 47 | * the <i>DSA</i> algorithm, "size" corresponds to the size | ||
| 48 | * of the prime modulus (in bits). | ||
| 49 | * When using this approach, algorithm-specific parameter generation | ||
| 50 | * values - if any - default to some standard values, unless they can be | ||
| 51 | * derived from the specified size.<P> | ||
| 52 | * | ||
| 53 | * <li>The other approach initializes a parameter generator object | ||
| 54 | * using algorithm-specific semantics, which are represented by a set of | ||
| 55 | * algorithm-specific parameter generation values. To generate | ||
| 56 | * Diffie-Hellman system parameters, for example, the parameter generation | ||
| 57 | * values usually | ||
| 58 | * consist of the size of the prime modulus and the size of the | ||
| 59 | * random exponent, both specified in number of bits. | ||
| 60 | * </ul> | ||
| 61 | * | ||
| 62 | * <P>In case the client does not explicitly initialize the | ||
| 63 | * AlgorithmParameterGenerator | ||
| 64 | * (via a call to an <code>init</code> method), each provider must supply (and | ||
| 65 | * document) a default initialization. For example, the Sun provider uses a | ||
| 66 | * default modulus prime size of 1024 bits for the generation of DSA | ||
| 67 | * parameters. | ||
| 68 | * | ||
| 69 | * <p> Every implementation of the Java platform is required to support the | ||
| 70 | * following standard <code>AlgorithmParameterGenerator</code> algorithms and | ||
| 71 | * keysizes in parentheses: | ||
| 72 | * <ul> | ||
| 73 | * <li><tt>DiffieHellman</tt> (1024)</li> | ||
| 74 | * <li><tt>DSA</tt> (1024)</li> | ||
| 75 | * </ul> | ||
| 76 | * These algorithms are described in the <a href= | ||
| 77 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameterGenerator"> | ||
| 78 | * AlgorithmParameterGenerator section</a> of the | ||
| 79 | * Java Cryptography Architecture Standard Algorithm Name Documentation. | ||
| 80 | * Consult the release documentation for your implementation to see if any | ||
| 81 | * other algorithms are supported. | ||
| 82 | * | ||
| 83 | * @author Jan Luehe | ||
| 84 | * | ||
| 85 | * | ||
| 86 | * @see AlgorithmParameters | ||
| 87 | * @see java.security.spec.AlgorithmParameterSpec | ||
| 88 | * | ||
| 89 | * @since 1.2 | ||
| 90 | */ | ||
| 91 | |||
| 92 | public class AlgorithmParameterGenerator { | ||
| 93 | |||
| 94 | // The provider | ||
| 95 | private Provider provider; | ||
| 96 | |||
| 97 | // The provider implementation (delegate) | ||
| 98 | private AlgorithmParameterGeneratorSpi paramGenSpi; | ||
| 99 | |||
| 100 | // The algorithm | ||
| 101 | private String algorithm; | ||
| 102 | |||
| 103 | /** | ||
| 104 | * Creates an AlgorithmParameterGenerator object. | ||
| 105 | * | ||
| 106 | * @param paramGenSpi the delegate | ||
| 107 | * @param provider the provider | ||
| 108 | * @param algorithm the algorithm | ||
| 109 | */ | ||
| 110 | protected AlgorithmParameterGenerator | ||
| 111 | (AlgorithmParameterGeneratorSpi paramGenSpi, Provider provider, | ||
| 112 | String algorithm) { | ||
| 113 | this.paramGenSpi = paramGenSpi; | ||
| 114 | this.provider = provider; | ||
| 115 | this.algorithm = algorithm; | ||
| 116 | } | ||
| 117 | |||
| 118 | /** | ||
| 119 | * Returns the standard name of the algorithm this parameter | ||
| 120 | * generator is associated with. | ||
| 121 | * | ||
| 122 | * @return the string name of the algorithm. | ||
| 123 | */ | ||
| 124 | public final String getAlgorithm() { | ||
| 125 | return this.algorithm; | ||
| 126 | } | ||
| 127 | |||
| 128 | /** | ||
| 129 | * Returns an AlgorithmParameterGenerator object for generating | ||
| 130 | * a set of parameters to be used with the specified algorithm. | ||
| 131 | * | ||
| 132 | * <p> This method traverses the list of registered security Providers, | ||
| 133 | * starting with the most preferred Provider. | ||
| 134 | * A new AlgorithmParameterGenerator object encapsulating the | ||
| 135 | * AlgorithmParameterGeneratorSpi implementation from the first | ||
| 136 | * Provider that supports the specified algorithm is returned. | ||
| 137 | * | ||
| 138 | * <p> Note that the list of registered providers may be retrieved via | ||
| 139 | * the {@link Security#getProviders() Security.getProviders()} method. | ||
| 140 | * | ||
| 141 | * @param algorithm the name of the algorithm this | ||
| 142 | * parameter generator is associated with. | ||
| 143 | * See the AlgorithmParameterGenerator section in the <a href= | ||
| 144 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameterGenerator"> | ||
| 145 | * Java Cryptography Architecture Standard Algorithm Name Documentation</a> | ||
| 146 | * for information about standard algorithm names. | ||
| 147 | * | ||
| 148 | * @return the new AlgorithmParameterGenerator object. | ||
| 149 | * | ||
| 150 | * @exception NoSuchAlgorithmException if no Provider supports an | ||
| 151 | * AlgorithmParameterGeneratorSpi implementation for the | ||
| 152 | * specified algorithm. | ||
| 153 | * | ||
| 154 | * @see Provider | ||
| 155 | */ | ||
| 156 | public static AlgorithmParameterGenerator getInstance(String algorithm) | ||
| 157 | throws NoSuchAlgorithmException { | ||
| 158 | try { | ||
| 159 | Object[] objs = Security.getImpl(algorithm, | ||
| 160 | "AlgorithmParameterGenerator", | ||
| 161 | (String)null); | ||
| 162 | return new AlgorithmParameterGenerator | ||
| 163 | ((AlgorithmParameterGeneratorSpi)objs[0], | ||
| 164 | (Provider)objs[1], | ||
| 165 | algorithm); | ||
| 166 | } catch(NoSuchProviderException e) { | ||
| 167 | throw new NoSuchAlgorithmException(algorithm + " not found"); | ||
| 168 | } | ||
| 169 | } | ||
| 170 | |||
| 171 | /** | ||
| 172 | * Returns an AlgorithmParameterGenerator object for generating | ||
| 173 | * a set of parameters to be used with the specified algorithm. | ||
| 174 | * | ||
| 175 | * <p> A new AlgorithmParameterGenerator object encapsulating the | ||
| 176 | * AlgorithmParameterGeneratorSpi implementation from the specified provider | ||
| 177 | * is returned. The specified provider must be registered | ||
| 178 | * in the security provider list. | ||
| 179 | * | ||
| 180 | * <p> Note that the list of registered providers may be retrieved via | ||
| 181 | * the {@link Security#getProviders() Security.getProviders()} method. | ||
| 182 | * | ||
| 183 | * @param algorithm the name of the algorithm this | ||
| 184 | * parameter generator is associated with. | ||
| 185 | * See the AlgorithmParameterGenerator section in the <a href= | ||
| 186 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameterGenerator"> | ||
| 187 | * Java Cryptography Architecture Standard Algorithm Name Documentation</a> | ||
| 188 | * for information about standard algorithm names. | ||
| 189 | * | ||
| 190 | * @param provider the string name of the Provider. | ||
| 191 | * | ||
| 192 | * @return the new AlgorithmParameterGenerator object. | ||
| 193 | * | ||
| 194 | * @exception NoSuchAlgorithmException if an AlgorithmParameterGeneratorSpi | ||
| 195 | * implementation for the specified algorithm is not | ||
| 196 | * available from the specified provider. | ||
| 197 | * | ||
| 198 | * @exception NoSuchProviderException if the specified provider is not | ||
| 199 | * registered in the security provider list. | ||
| 200 | * | ||
| 201 | * @exception IllegalArgumentException if the provider name is null | ||
| 202 | * or empty. | ||
| 203 | * | ||
| 204 | * @see Provider | ||
| 205 | */ | ||
| 206 | public static AlgorithmParameterGenerator getInstance(String algorithm, | ||
| 207 | String provider) | ||
| 208 | throws NoSuchAlgorithmException, NoSuchProviderException | ||
| 209 | { | ||
| 210 | if (provider == null || provider.length() == 0) | ||
| 211 | throw new IllegalArgumentException("missing provider"); | ||
| 212 | Object[] objs = Security.getImpl(algorithm, | ||
| 213 | "AlgorithmParameterGenerator", | ||
| 214 | provider); | ||
| 215 | return new AlgorithmParameterGenerator | ||
| 216 | ((AlgorithmParameterGeneratorSpi)objs[0], (Provider)objs[1], | ||
| 217 | algorithm); | ||
| 218 | } | ||
| 219 | |||
| 220 | /** | ||
| 221 | * Returns an AlgorithmParameterGenerator object for generating | ||
| 222 | * a set of parameters to be used with the specified algorithm. | ||
| 223 | * | ||
| 224 | * <p> A new AlgorithmParameterGenerator object encapsulating the | ||
| 225 | * AlgorithmParameterGeneratorSpi implementation from the specified Provider | ||
| 226 | * object is returned. Note that the specified Provider object | ||
| 227 | * does not have to be registered in the provider list. | ||
| 228 | * | ||
| 229 | * @param algorithm the string name of the algorithm this | ||
| 230 | * parameter generator is associated with. | ||
| 231 | * See the AlgorithmParameterGenerator section in the <a href= | ||
| 232 | * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameterGenerator"> | ||
| 233 | * Java Cryptography Architecture Standard Algorithm Name Documentation</a> | ||
| 234 | * for information about standard algorithm names. | ||
| 235 | * | ||
| 236 | * @param provider the Provider object. | ||
| 237 | * | ||
| 238 | * @return the new AlgorithmParameterGenerator object. | ||
| 239 | * | ||
| 240 | * @exception NoSuchAlgorithmException if an AlgorithmParameterGeneratorSpi | ||
| 241 | * implementation for the specified algorithm is not available | ||
| 242 | * from the specified Provider object. | ||
| 243 | * | ||
| 244 | * @exception IllegalArgumentException if the specified provider is null. | ||
| 245 | * | ||
| 246 | * @see Provider | ||
| 247 | * | ||
| 248 | * @since 1.4 | ||
| 249 | */ | ||
| 250 | public static AlgorithmParameterGenerator getInstance(String algorithm, | ||
| 251 | Provider provider) | ||
| 252 | throws NoSuchAlgorithmException | ||
| 253 | { | ||
| 254 | if (provider == null) | ||
| 255 | throw new IllegalArgumentException("missing provider"); | ||
| 256 | Object[] objs = Security.getImpl(algorithm, | ||
| 257 | "AlgorithmParameterGenerator", | ||
| 258 | provider); | ||
| 259 | return new AlgorithmParameterGenerator | ||
| 260 | ((AlgorithmParameterGeneratorSpi)objs[0], (Provider)objs[1], | ||
| 261 | algorithm); | ||
| 262 | } | ||
| 263 | |||
| 264 | /** | ||
| 265 | * Returns the provider of this algorithm parameter generator object. | ||
| 266 | * | ||
| 267 | * @return the provider of this algorithm parameter generator object | ||
| 268 | */ | ||
| 269 | public final Provider getProvider() { | ||
| 270 | return this.provider; | ||
| 271 | } | ||
| 272 | |||
| 273 | /** | ||
| 274 | * Initializes this parameter generator for a certain size. | ||
| 275 | * To create the parameters, the <code>SecureRandom</code> | ||
| 276 | * implementation of the highest-priority installed provider is used as | ||
| 277 | * the source of randomness. | ||
| 278 | * (If none of the installed providers supply an implementation of | ||
| 279 | * <code>SecureRandom</code>, a system-provided source of randomness is | ||
| 280 | * used.) | ||
| 281 | * | ||
| 282 | * @param size the size (number of bits). | ||
| 283 | */ | ||
| 284 | public final void init(int size) { | ||
| 285 | paramGenSpi.engineInit(size, new SecureRandom()); | ||
| 286 | } | ||
| 287 | |||
| 288 | /** | ||
| 289 | * Initializes this parameter generator for a certain size and source | ||
| 290 | * of randomness. | ||
| 291 | * | ||
| 292 | * @param size the size (number of bits). | ||
| 293 | * @param random the source of randomness. | ||
| 294 | */ | ||
| 295 | public final void init(int size, SecureRandom random) { | ||
| 296 | paramGenSpi.engineInit(size, random); | ||
| 297 | } | ||
| 298 | |||
| 299 | /** | ||
| 300 | * Initializes this parameter generator with a set of algorithm-specific | ||
| 301 | * parameter generation values. | ||
| 302 | * To generate the parameters, the <code>SecureRandom</code> | ||
| 303 | * implementation of the highest-priority installed provider is used as | ||
| 304 | * the source of randomness. | ||
| 305 | * (If none of the installed providers supply an implementation of | ||
| 306 | * <code>SecureRandom</code>, a system-provided source of randomness is | ||
| 307 | * used.) | ||
| 308 | * | ||
| 309 | * @param genParamSpec the set of algorithm-specific parameter generation values. | ||
| 310 | * | ||
| 311 | * @exception InvalidAlgorithmParameterException if the given parameter | ||
| 312 | * generation values are inappropriate for this parameter generator. | ||
| 313 | */ | ||
| 314 | public final void init(AlgorithmParameterSpec genParamSpec) | ||
| 315 | throws InvalidAlgorithmParameterException { | ||
| 316 | paramGenSpi.engineInit(genParamSpec, new SecureRandom()); | ||
| 317 | } | ||
| 318 | |||
| 319 | /** | ||
| 320 | * Initializes this parameter generator with a set of algorithm-specific | ||
| 321 | * parameter generation values. | ||
| 322 | * | ||
| 323 | * @param genParamSpec the set of algorithm-specific parameter generation values. | ||
| 324 | * @param random the source of randomness. | ||
| 325 | * | ||
| 326 | * @exception InvalidAlgorithmParameterException if the given parameter | ||
| 327 | * generation values are inappropriate for this parameter generator. | ||
| 328 | */ | ||
| 329 | public final void init(AlgorithmParameterSpec genParamSpec, | ||
| 330 | SecureRandom random) | ||
| 331 | throws InvalidAlgorithmParameterException { | ||
| 332 | paramGenSpi.engineInit(genParamSpec, random); | ||
| 333 | } | ||
| 334 | |||
| 335 | /** | ||
| 336 | * Generates the parameters. | ||
| 337 | * | ||
| 338 | * @return the new AlgorithmParameters object. | ||
| 339 | */ | ||
| 340 | public final AlgorithmParameters generateParameters() { | ||
| 341 | return paramGenSpi.engineGenerateParameters(); | ||
| 342 | } | ||
| 343 | } | ||