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.lang.CPStringBuilder;
042
043 import gnu.java.security.Engine;
044
045 import java.lang.reflect.InvocationTargetException;
046 import java.security.spec.InvalidKeySpecException;
047 import java.security.spec.KeySpec;
048
049 /**
050 * Key factories are used to convert keys (opaque cryptographic keys of type
051 * {@link Key}) into key specifications (transparent representations of the
052 * underlying key material).
053 *
054 * <p>Key factories are bi-directional. They allow a key class to be converted
055 * into a key specification (key material) and back again. For example DSA
056 * public keys can be specified as <code>DSAPublicKeySpec</code> or
057 * <code>X509EncodedKeySpec</code>. A key factory translates these key
058 * specifications.</p>
059 *
060 * @since 1.2
061 * @see Key
062 * @see KeySpec
063 * @see java.security.spec.DSAPublicKeySpec
064 * @see java.security.spec.X509EncodedKeySpec
065 @author Mark Benvenuto
066 */
067 public class KeyFactory
068 {
069 /** The service name for key factories. */
070 private static final String KEY_FACTORY = "KeyFactory";
071
072 private KeyFactorySpi keyFacSpi;
073 private Provider provider;
074 private String algorithm;
075
076 /**
077 * Constructs a new instance of <code>KeyFactory</code> with the specified
078 * parameters.
079 *
080 * @param keyFacSpi
081 * the key factory to use.
082 * @param provider
083 * the provider to use.
084 * @param algorithm
085 * the name of the key algorithm to use.
086 */
087 protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider,
088 String algorithm)
089 {
090 this.keyFacSpi = keyFacSpi;
091 this.provider = provider;
092 this.algorithm = algorithm;
093 }
094
095 /**
096 * Returns a new instance of <code>KeyFactory</code> representing the
097 * specified key factory.
098 *
099 * @param algorithm the name of algorithm to use.
100 * @return a new instance repesenting the desired algorithm.
101 * @throws NoSuchAlgorithmException if the algorithm is not implemented by any
102 * provider.
103 * @throws IllegalArgumentException if <code>algorithm</code> is
104 * <code>null</code> or is an empty string.
105 */
106 public static KeyFactory getInstance(String algorithm)
107 throws NoSuchAlgorithmException
108 {
109 Provider[] p = Security.getProviders();
110 NoSuchAlgorithmException lastException = null;
111 for (int i = 0; i < p.length; i++)
112 try
113 {
114 return getInstance(algorithm, p[i]);
115 }
116 catch (NoSuchAlgorithmException x)
117 {
118 lastException = x;
119 }
120 if (lastException != null)
121 throw lastException;
122 throw new NoSuchAlgorithmException(algorithm);
123 }
124
125 /**
126 * Returns a new instance of <code>KeyFactory</code> representing the
127 * specified key factory from the specified provider.
128 *
129 * @param algorithm the name of algorithm to use.
130 * @param provider the name of the provider to use.
131 * @return a new instance repesenting the desired algorithm.
132 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the
133 * named provider.
134 * @throws NoSuchProviderException if the named provider was not found.
135 * @throws IllegalArgumentException if either <code>algorithm</code> or
136 * <code>provider</code> is <code>null</code> or empty.
137 */
138 public static KeyFactory getInstance(String algorithm, String provider)
139 throws NoSuchAlgorithmException, NoSuchProviderException
140 {
141 if (provider == null)
142 throw new IllegalArgumentException("provider MUST NOT be null");
143 provider = provider.trim();
144 if (provider.length() == 0)
145 throw new IllegalArgumentException("provider MUST NOT be empty");
146 Provider p = Security.getProvider(provider);
147 if (p == null)
148 throw new NoSuchProviderException(provider);
149 return getInstance(algorithm, p);
150 }
151
152 /**
153 * Returns a new instance of <code>KeyFactory</code> representing the
154 * specified key factory from the designated {@link Provider}.
155 *
156 * @param algorithm the name of algorithm to use.
157 * @param provider the {@link Provider} to use.
158 * @return a new instance repesenting the desired algorithm.
159 * @throws NoSuchAlgorithmException if the algorithm is not implemented by
160 * {@link Provider}.
161 * @throws IllegalArgumentException if either <code>algorithm</code> or
162 * <code>provider</code> is <code>null</code>, or if
163 * <code>algorithm</code> is an empty string.
164 * @since 1.4
165 * @see Provider
166 */
167 public static KeyFactory getInstance(String algorithm, Provider provider)
168 throws NoSuchAlgorithmException
169 {
170 CPStringBuilder sb = new CPStringBuilder("KeyFactory for algorithm [")
171 .append(algorithm).append("] from provider[")
172 .append(provider).append("] could not be created");
173 Throwable cause;
174 try
175 {
176 Object spi = Engine.getInstance(KEY_FACTORY, algorithm, provider);
177 return new KeyFactory((KeyFactorySpi) spi, provider, algorithm);
178 }
179 catch (InvocationTargetException x)
180 {
181 cause = x.getCause();
182 if (cause instanceof NoSuchAlgorithmException)
183 throw (NoSuchAlgorithmException) cause;
184 if (cause == null)
185 cause = x;
186 }
187 catch (ClassCastException x)
188 {
189 cause = x;
190 }
191 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
192 x.initCause(cause);
193 throw x;
194 }
195
196 /**
197 * Returns the {@link Provider} of this instance.
198 *
199 * @return the {@link Provider} of this instance.
200 */
201 public final Provider getProvider()
202 {
203 return provider;
204 }
205
206 /**
207 * Returns the name of the algorithm used.
208 *
209 * @return the name of the algorithm used.
210 */
211 public final String getAlgorithm()
212 {
213 return algorithm;
214 }
215
216 /**
217 * Generates a public key from the provided key specification.
218 *
219 * @param keySpec
220 * the key specification.
221 * @return the public key.
222 * @throws InvalidKeySpecException
223 * if the key specification is invalid.
224 */
225 public final PublicKey generatePublic(KeySpec keySpec)
226 throws InvalidKeySpecException
227 {
228 return keyFacSpi.engineGeneratePublic(keySpec);
229 }
230
231 /**
232 * Generates a private key from the provided key specification.
233 *
234 * @param keySpec
235 * the key specification.
236 * @return the private key.
237 * @throws InvalidKeySpecException
238 * if the key specification is invalid.
239 */
240 public final PrivateKey generatePrivate(KeySpec keySpec)
241 throws InvalidKeySpecException
242 {
243 return keyFacSpi.engineGeneratePrivate(keySpec);
244 }
245
246 /**
247 * Returns a key specification for the given key. <code>keySpec</code>
248 * identifies the specification class to return the key material in.
249 *
250 * @param key
251 * the key to use.
252 * @param keySpec
253 * the specification class to use.
254 * @return the key specification in an instance of the requested specification
255 * class.
256 * @throws InvalidKeySpecException
257 * the requested key specification is inappropriate for this key or
258 * the key is unrecognized.
259 */
260 public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec)
261 throws InvalidKeySpecException
262 {
263 return keyFacSpi.engineGetKeySpec(key, keySpec);
264 }
265
266 /**
267 * Translates the key from an unknown or untrusted provider into a key from
268 * this key factory.
269 *
270 * @param key
271 * the key to translate from.
272 * @return the translated key.
273 * @throws InvalidKeyException
274 * if the key cannot be processed by this key factory.
275 */
276 public final Key translateKey(Key key) throws InvalidKeyException
277 {
278 return keyFacSpi.engineTranslateKey(key);
279 }
280 }