001 /* KeyFactory.java --- Key Factory Class
002 Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.security;
040
041 import gnu.java.security.Engine;
042
043 import java.lang.reflect.InvocationTargetException;
044 import java.security.spec.InvalidKeySpecException;
045 import java.security.spec.KeySpec;
046
047 /**
048 * Key factories are used to convert keys (opaque cryptographic keys of type
049 * {@link Key}) into key specifications (transparent representations of the
050 * underlying key material).
051 *
052 * <p>Key factories are bi-directional. They allow a key class to be converted
053 * into a key specification (key material) and back again. For example DSA
054 * public keys can be specified as <code>DSAPublicKeySpec</code> or
055 * <code>X509EncodedKeySpec</code>. A key factory translates these key
056 * specifications.</p>
057 *
058 * @since 1.2
059 * @see Key
060 * @see KeySpec
061 * @see java.security.spec.DSAPublicKeySpec
062 * @see java.security.spec.X509EncodedKeySpec
063 @author Mark Benvenuto
064 */
065 public class KeyFactory
066 {
067 /** The service name for key factories. */
068 private static final String KEY_FACTORY = "KeyFactory";
069
070 private KeyFactorySpi keyFacSpi;
071 private Provider provider;
072 private String algorithm;
073
074 /**
075 * Constructs a new instance of <code>KeyFactory</code> with the specified
076 * parameters.
077 *
078 * @param keyFacSpi
079 * the key factory to use.
080 * @param provider
081 * the provider to use.
082 * @param algorithm
083 * the name of the key algorithm to use.
084 */
085 protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider,
086 String algorithm)
087 {
088 this.keyFacSpi = keyFacSpi;
089 this.provider = provider;
090 this.algorithm = algorithm;
091 }
092
093 /**
094 * Returns a new instance of <code>KeyFactory</code> representing the
095 * specified key factory.
096 *
097 * @param algorithm the name of algorithm to use.
098 * @return a new instance repesenting the desired algorithm.
099 * @throws NoSuchAlgorithmException if the algorithm is not implemented by any
100 * provider.
101 * @throws IllegalArgumentException if <code>algorithm</code> is
102 * <code>null</code> or is an empty string.
103 */
104 public static KeyFactory getInstance(String algorithm)
105 throws NoSuchAlgorithmException
106 {
107 Provider[] p = Security.getProviders();
108 NoSuchAlgorithmException lastException = null;
109 for (int i = 0; i < p.length; i++)
110 try
111 {
112 return getInstance(algorithm, p[i]);
113 }
114 catch (NoSuchAlgorithmException x)
115 {
116 lastException = x;
117 }
118 if (lastException != null)
119 throw lastException;
120 throw new NoSuchAlgorithmException(algorithm);
121 }
122
123 /**
124 * Returns a new instance of <code>KeyFactory</code> representing the
125 * specified key factory from the specified provider.
126 *
127 * @param algorithm the name of algorithm to use.
128 * @param provider the name of the provider to use.
129 * @return a new instance repesenting the desired algorithm.
130 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the
131 * named provider.
132 * @throws NoSuchProviderException if the named provider was not found.
133 * @throws IllegalArgumentException if either <code>algorithm</code> or
134 * <code>provider</code> is <code>null</code> or empty.
135 */
136 public static KeyFactory getInstance(String algorithm, String provider)
137 throws NoSuchAlgorithmException, NoSuchProviderException
138 {
139 if (provider == null)
140 throw new IllegalArgumentException("provider MUST NOT be null");
141 provider = provider.trim();
142 if (provider.length() == 0)
143 throw new IllegalArgumentException("provider MUST NOT be empty");
144 Provider p = Security.getProvider(provider);
145 if (p == null)
146 throw new NoSuchProviderException(provider);
147 return getInstance(algorithm, p);
148 }
149
150 /**
151 * Returns a new instance of <code>KeyFactory</code> representing the
152 * specified key factory from the designated {@link Provider}.
153 *
154 * @param algorithm the name of algorithm to use.
155 * @param provider the {@link Provider} to use.
156 * @return a new instance repesenting the desired algorithm.
157 * @throws NoSuchAlgorithmException if the algorithm is not implemented by
158 * {@link Provider}.
159 * @throws IllegalArgumentException if either <code>algorithm</code> or
160 * <code>provider</code> is <code>null</code>, or if
161 * <code>algorithm</code> is an empty string.
162 * @since 1.4
163 * @see Provider
164 */
165 public static KeyFactory getInstance(String algorithm, Provider provider)
166 throws NoSuchAlgorithmException
167 {
168 StringBuilder sb = new StringBuilder("KeyFactory for algorithm [")
169 .append(algorithm).append("] from provider[")
170 .append(provider).append("] could not be created");
171 Throwable cause;
172 try
173 {
174 Object spi = Engine.getInstance(KEY_FACTORY, algorithm, provider);
175 return new KeyFactory((KeyFactorySpi) spi, provider, algorithm);
176 }
177 catch (InvocationTargetException x)
178 {
179 cause = x.getCause();
180 if (cause instanceof NoSuchAlgorithmException)
181 throw (NoSuchAlgorithmException) cause;
182 if (cause == null)
183 cause = x;
184 }
185 catch (ClassCastException x)
186 {
187 cause = x;
188 }
189 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
190 x.initCause(cause);
191 throw x;
192 }
193
194 /**
195 * Returns the {@link Provider} of this instance.
196 *
197 * @return the {@link Provider} of this instance.
198 */
199 public final Provider getProvider()
200 {
201 return provider;
202 }
203
204 /**
205 * Returns the name of the algorithm used.
206 *
207 * @return the name of the algorithm used.
208 */
209 public final String getAlgorithm()
210 {
211 return algorithm;
212 }
213
214 /**
215 * Generates a public key from the provided key specification.
216 *
217 * @param keySpec
218 * the key specification.
219 * @return the public key.
220 * @throws InvalidKeySpecException
221 * if the key specification is invalid.
222 */
223 public final PublicKey generatePublic(KeySpec keySpec)
224 throws InvalidKeySpecException
225 {
226 return keyFacSpi.engineGeneratePublic(keySpec);
227 }
228
229 /**
230 * Generates a private key from the provided key specification.
231 *
232 * @param keySpec
233 * the key specification.
234 * @return the private key.
235 * @throws InvalidKeySpecException
236 * if the key specification is invalid.
237 */
238 public final PrivateKey generatePrivate(KeySpec keySpec)
239 throws InvalidKeySpecException
240 {
241 return keyFacSpi.engineGeneratePrivate(keySpec);
242 }
243
244 /**
245 * Returns a key specification for the given key. <code>keySpec</code>
246 * identifies the specification class to return the key material in.
247 *
248 * @param key
249 * the key to use.
250 * @param keySpec
251 * the specification class to use.
252 * @return the key specification in an instance of the requested specification
253 * class.
254 * @throws InvalidKeySpecException
255 * the requested key specification is inappropriate for this key or
256 * the key is unrecognized.
257 */
258 public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec)
259 throws InvalidKeySpecException
260 {
261 return keyFacSpi.engineGetKeySpec(key, keySpec);
262 }
263
264 /**
265 * Translates the key from an unknown or untrusted provider into a key from
266 * this key factory.
267 *
268 * @param key
269 * the key to translate from.
270 * @return the translated key.
271 * @throws InvalidKeyException
272 * if the key cannot be processed by this key factory.
273 */
274 public final Key translateKey(Key key) throws InvalidKeyException
275 {
276 return keyFacSpi.engineTranslateKey(key);
277 }
278 }