1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation. Oracle designates this
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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).
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24 */
25
26 package java.security;
27
28 import java.io.*;
29 import java.security.spec.AlgorithmParameterSpec;
30 import java.security.spec.InvalidParameterSpecException;
31
32 /**
33 * This class is used as an opaque representation of cryptographic parameters.
34 *
35 * <p>An {@code AlgorithmParameters} object for managing the parameters
36 * for a particular algorithm can be obtained by
37 * calling one of the {@code getInstance} factory methods
38 * (static methods that return instances of a given class).
39 *
40 * <p>Once an {@code AlgorithmParameters} object is obtained, it must be
41 * initialized via a call to {@code init}, using an appropriate parameter
42 * specification or parameter encoding.
43 *
44 * <p>A transparent parameter specification is obtained from an
45 * {@code AlgorithmParameters} object via a call to
46 * {@code getParameterSpec}, and a byte encoding of the parameters is
47 * obtained via a call to {@code getEncoded}.
48 *
49 * <p> Every implementation of the Java platform is required to support the
50 * following standard {@code AlgorithmParameters} algorithms:
51 * <ul>
52 * <li>{@code AES}</li>
53 * <li>{@code DES}</li>
54 * <li>{@code DESede}</li>
55 * <li>{@code DiffieHellman}</li>
56 * <li>{@code DSA}</li>
57 * </ul>
58 * These algorithms are described in the <a href=
59 * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameters">
60 * AlgorithmParameters section</a> of the
61 * Java Cryptography Architecture Standard Algorithm Name Documentation.
62 * Consult the release documentation for your implementation to see if any
63 * other algorithms are supported.
64 *
65 * @author Jan Luehe
66 *
67 *
68 * @see java.security.spec.AlgorithmParameterSpec
69 * @see java.security.spec.DSAParameterSpec
70 * @see KeyPairGenerator
71 *
72 * @since 1.2
73 */
74
75 public class AlgorithmParameters {
76
77 // The provider
78 private Provider provider;
79
80 // The provider implementation (delegate)
81 private AlgorithmParametersSpi paramSpi;
82
83 // The algorithm
84 private String algorithm;
85
86 // Has this object been initialized?
87 private boolean initialized = false;
88
89 /**
90 * Creates an AlgorithmParameters object.
91 *
92 * @param paramSpi the delegate
93 * @param provider the provider
94 * @param algorithm the algorithm
95 */
96 protected AlgorithmParameters(AlgorithmParametersSpi paramSpi,
97 Provider provider, String algorithm)
98 {
99 this.paramSpi = paramSpi;
100 this.provider = provider;
101 this.algorithm = algorithm;
102 }
103
104 /**
105 * Returns the name of the algorithm associated with this parameter object.
106 *
107 * @return the algorithm name.
108 */
109 public final String getAlgorithm() {
110 return this.algorithm;
111 }
112
113 /**
114 * Returns a parameter object for the specified algorithm.
115 *
116 * <p> This method traverses the list of registered security Providers,
117 * starting with the most preferred Provider.
118 * A new AlgorithmParameters object encapsulating the
119 * AlgorithmParametersSpi implementation from the first
120 * Provider that supports the specified algorithm is returned.
121 *
122 * <p> Note that the list of registered providers may be retrieved via
123 * the {@link Security#getProviders() Security.getProviders()} method.
124 *
125 * <p> The returned parameter object must be initialized via a call to
126 * {@code init}, using an appropriate parameter specification or
127 * parameter encoding.
128 *
129 * @implNote
130 * The JDK Reference Implementation additionally uses the
131 * {@code jdk.security.provider.preferred} property to determine
132 * the preferred provider order for the specified algorithm. This
133 * may be different than the order of providers returned by
134 * {@link Security#getProviders() Security.getProviders()}.
135 *
136 * @param algorithm the name of the algorithm requested.
137 * See the AlgorithmParameters section in the <a href=
138 * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameters">
139 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
140 * for information about standard algorithm names.
141 *
142 * @return the new parameter object.
143 *
144 * @exception NoSuchAlgorithmException if no Provider supports an
145 * AlgorithmParametersSpi implementation for the
146 * specified algorithm.
147 *
148 * @see Provider
149 */
150 public static AlgorithmParameters getInstance(String algorithm)
151 throws NoSuchAlgorithmException {
152 try {
153 Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
154 (String)null);
155 return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
156 (Provider)objs[1],
157 algorithm);
158 } catch(NoSuchProviderException e) {
159 throw new NoSuchAlgorithmException(algorithm + " not found");
160 }
161 }
162
163 /**
164 * Returns a parameter object for the specified algorithm.
165 *
166 * <p> A new AlgorithmParameters object encapsulating the
167 * AlgorithmParametersSpi 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 * <p>The returned parameter object must be initialized via a call to
175 * {@code init}, using an appropriate parameter specification or
176 * parameter encoding.
177 *
178 * @param algorithm the name of the algorithm requested.
179 * See the AlgorithmParameters section in the <a href=
180 * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameters">
181 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
182 * for information about standard algorithm names.
183 *
184 * @param provider the name of the provider.
185 *
186 * @return the new parameter object.
187 *
188 * @exception NoSuchAlgorithmException if an AlgorithmParametersSpi
189 * implementation for the specified algorithm is not
190 * available from the specified provider.
191 *
192 * @exception NoSuchProviderException if the specified provider is not
193 * registered in the security provider list.
194 *
195 * @exception IllegalArgumentException if the provider name is null
196 * or empty.
197 *
198 * @see Provider
199 */
200 public static AlgorithmParameters getInstance(String algorithm,
201 String provider)
202 throws NoSuchAlgorithmException, NoSuchProviderException
203 {
204 if (provider == null || provider.length() == 0)
205 throw new IllegalArgumentException("missing provider");
206 Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
207 provider);
208 return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
209 (Provider)objs[1],
210 algorithm);
211 }
212
213 /**
214 * Returns a parameter object for the specified algorithm.
215 *
216 * <p> A new AlgorithmParameters object encapsulating the
217 * AlgorithmParametersSpi implementation from the specified Provider
218 * object is returned. Note that the specified Provider object
219 * does not have to be registered in the provider list.
220 *
221 * <p>The returned parameter object must be initialized via a call to
222 * {@code init}, using an appropriate parameter specification or
223 * parameter encoding.
224 *
225 * @param algorithm the name of the algorithm requested.
226 * See the AlgorithmParameters section in the <a href=
227 * "{@docRoot}/../technotes/guides/security/StandardNames.html#AlgorithmParameters">
228 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
229 * for information about standard algorithm names.
230 *
231 * @param provider the name of the provider.
232 *
233 * @return the new parameter object.
234 *
235 * @exception NoSuchAlgorithmException if an AlgorithmParameterGeneratorSpi
236 * implementation for the specified algorithm is not available
237 * from the specified Provider object.
238 *
239 * @exception IllegalArgumentException if the provider is null.
240 *
241 * @see Provider
242 *
243 * @since 1.4
244 */
245 public static AlgorithmParameters getInstance(String algorithm,
246 Provider provider)
247 throws NoSuchAlgorithmException
248 {
249 if (provider == null)
250 throw new IllegalArgumentException("missing provider");
251 Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
252 provider);
253 return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
254 (Provider)objs[1],
255 algorithm);
256 }
257
258 /**
259 * Returns the provider of this parameter object.
260 *
261 * @return the provider of this parameter object
262 */
263 public final Provider getProvider() {
264 return this.provider;
265 }
266
267 /**
268 * Initializes this parameter object using the parameters
269 * specified in {@code paramSpec}.
270 *
271 * @param paramSpec the parameter specification.
272 *
273 * @exception InvalidParameterSpecException if the given parameter
274 * specification is inappropriate for the initialization of this parameter
275 * object, or if this parameter object has already been initialized.
276 */
277 public final void init(AlgorithmParameterSpec paramSpec)
278 throws InvalidParameterSpecException
279 {
280 if (this.initialized)
281 throw new InvalidParameterSpecException("already initialized");
282 paramSpi.engineInit(paramSpec);
283 this.initialized = true;
284 }
285
286 /**
287 * Imports the specified parameters and decodes them according to the
288 * primary decoding format for parameters. The primary decoding
289 * format for parameters is ASN.1, if an ASN.1 specification for this type
290 * of parameters exists.
291 *
292 * @param params the encoded parameters.
293 *
294 * @exception IOException on decoding errors, or if this parameter object
295 * has already been initialized.
296 */
297 public final void init(byte[] params) throws IOException {
298 if (this.initialized)
299 throw new IOException("already initialized");
300 paramSpi.engineInit(params);
301 this.initialized = true;
302 }
303
304 /**
305 * Imports the parameters from {@code params} and decodes them
306 * according to the specified decoding scheme.
307 * If {@code format} is null, the
308 * primary decoding format for parameters is used. The primary decoding
309 * format is ASN.1, if an ASN.1 specification for these parameters
310 * exists.
311 *
312 * @param params the encoded parameters.
313 *
314 * @param format the name of the decoding scheme.
315 *
316 * @exception IOException on decoding errors, or if this parameter object
317 * has already been initialized.
318 */
319 public final void init(byte[] params, String format) throws IOException {
320 if (this.initialized)
321 throw new IOException("already initialized");
322 paramSpi.engineInit(params, format);
323 this.initialized = true;
324 }
325
326 /**
327 * Returns a (transparent) specification of this parameter object.
328 * {@code paramSpec} identifies the specification class in which
329 * the parameters should be returned. It could, for example, be
330 * {@code DSAParameterSpec.class}, to indicate that the
331 * parameters should be returned in an instance of the
332 * {@code DSAParameterSpec} class.
333 *
334 * @param <T> the type of the parameter specification to be returrned
335 * @param paramSpec the specification class in which
336 * the parameters should be returned.
337 *
338 * @return the parameter specification.
339 *
340 * @exception InvalidParameterSpecException if the requested parameter
341 * specification is inappropriate for this parameter object, or if this
342 * parameter object has not been initialized.
343 */
344 public final <T extends AlgorithmParameterSpec>
345 T getParameterSpec(Class<T> paramSpec)
346 throws InvalidParameterSpecException
347 {
348 if (this.initialized == false) {
349 throw new InvalidParameterSpecException("not initialized");
350 }
351 return paramSpi.engineGetParameterSpec(paramSpec);
352 }
353
354 /**
355 * Returns the parameters in their primary encoding format.
356 * The primary encoding format for parameters is ASN.1, if an ASN.1
357 * specification for this type of parameters exists.
358 *
359 * @return the parameters encoded using their primary encoding format.
360 *
361 * @exception IOException on encoding errors, or if this parameter object
362 * has not been initialized.
363 */
364 public final byte[] getEncoded() throws IOException
365 {
366 if (this.initialized == false) {
367 throw new IOException("not initialized");
368 }
369 return paramSpi.engineGetEncoded();
370 }
371
372 /**
373 * Returns the parameters encoded in the specified scheme.
374 * If {@code format} is null, the
375 * primary encoding format for parameters is used. The primary encoding
376 * format is ASN.1, if an ASN.1 specification for these parameters
377 * exists.
378 *
379 * @param format the name of the encoding format.
380 *
381 * @return the parameters encoded using the specified encoding scheme.
382 *
383 * @exception IOException on encoding errors, or if this parameter object
384 * has not been initialized.
385 */
386 public final byte[] getEncoded(String format) throws IOException
387 {
388 if (this.initialized == false) {
389 throw new IOException("not initialized");
390 }
391 return paramSpi.engineGetEncoded(format);
392 }
393
394 /**
395 * Returns a formatted string describing the parameters.
396 *
397 * @return a formatted string describing the parameters, or null if this
398 * parameter object has not been initialized.
399 */
400 public final String toString() {
401 if (this.initialized == false) {
402 return null;
403 }
404 return paramSpi.engineToString();
405 }
406 }