001 /* SecretKeyFactory.java -- Factory for creating secret keys.
002 Copyright (C) 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 javax.crypto;
040
041 import gnu.java.security.Engine;
042
043 import java.lang.reflect.InvocationTargetException;
044 import java.security.InvalidKeyException;
045 import java.security.NoSuchAlgorithmException;
046 import java.security.NoSuchProviderException;
047 import java.security.Provider;
048 import java.security.Security;
049 import java.security.spec.InvalidKeySpecException;
050 import java.security.spec.KeySpec;
051
052 /**
053 * A secret key factory translates {@link SecretKey} objects to and from
054 * {@link java.security.spec.KeySpec} objects, and can translate between
055 * different vendors' representations of {@link SecretKey} objects (for
056 * security or semantics; whichever applies).
057 *
058 * @author Casey Marshall (csm@gnu.org)
059 * @since 1.4
060 * @see SecretKey
061 */
062 public class SecretKeyFactory
063 {
064
065 // Constants and fields.
066 // ------------------------------------------------------------------------
067
068 private static final String SERVICE = "SecretKeyFactory";
069
070 /** The underlying factory implementation. */
071 private SecretKeyFactorySpi skfSpi;
072
073 /** The provider of the implementation. */
074 private Provider provider;
075
076 /** The name of the algorithm. */
077 private String algorithm;
078
079 // Constructor.
080 // ------------------------------------------------------------------------
081
082 /**
083 * Create a new secret key factory.
084 *
085 * @param skfSpi The underlying factory implementation.
086 * @param provider The provider.
087 * @param algorithm The algorithm name.
088 */
089 protected SecretKeyFactory(SecretKeyFactorySpi skfSpi, Provider provider,
090 String algorithm)
091 {
092 this.skfSpi = skfSpi;
093 this.provider = provider;
094 this.algorithm = algorithm;
095 }
096
097 /**
098 * Create a new secret key factory from the first appropriate instance.
099 *
100 * @param algorithm The algorithm name.
101 * @return The appropriate key factory, if found.
102 * @throws NoSuchAlgorithmException If no provider implements the specified
103 * algorithm.
104 * @throws IllegalArgumentException if <code>algorithm</code> is
105 * <code>null</code> or is an empty string.
106 */
107 public static final SecretKeyFactory getInstance(String algorithm)
108 throws NoSuchAlgorithmException
109 {
110 Provider[] p = Security.getProviders();
111 NoSuchAlgorithmException lastException = null;
112 for (int i = 0; i < p.length; i++)
113 try
114 {
115 return getInstance(algorithm, p[i]);
116 }
117 catch (NoSuchAlgorithmException x)
118 {
119 lastException = x;
120 }
121 if (lastException != null)
122 throw lastException;
123 throw new NoSuchAlgorithmException(algorithm);
124 }
125
126 /**
127 * Create a new secret key factory from the named provider.
128 *
129 * @param algorithm The algorithm name.
130 * @param provider The provider name.
131 * @return The appropriate key factory, if found.
132 * @throws NoSuchAlgorithmException If the named provider does not implement
133 * the algorithm.
134 * @throws NoSuchProviderException If the named provider does not exist.
135 * @throws IllegalArgumentException if either <code>algorithm</code> or
136 * <code>provider</code> is <code>null</code>, or if
137 * <code>algorithm</code> is an empty string.
138 */
139 public static final SecretKeyFactory getInstance(String algorithm,
140 String provider)
141 throws NoSuchAlgorithmException, NoSuchProviderException
142 {
143 if (provider == null)
144 throw new IllegalArgumentException("provider MUST NOT be null");
145 Provider p = Security.getProvider(provider);
146 if (p == null)
147 throw new NoSuchProviderException(provider);
148 return getInstance(algorithm, p);
149 }
150
151 /**
152 * Create a new secret key factory from the specified provider.
153 *
154 * @param algorithm The algorithm name.
155 * @param provider The provider.
156 * @return The appropriate key factory, if found.
157 * @throws NoSuchAlgorithmException If the provider does not implement the
158 * algorithm.
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 */
163 public static final SecretKeyFactory getInstance(String algorithm,
164 Provider provider)
165 throws NoSuchAlgorithmException
166 {
167 StringBuilder sb = new StringBuilder("SecretKeyFactory algorithm [")
168 .append(algorithm).append("] from provider[")
169 .append(provider).append("] could not be created");
170 Throwable cause;
171 try
172 {
173 Object spi = Engine.getInstance(SERVICE, algorithm, provider);
174 return new SecretKeyFactory((SecretKeyFactorySpi) spi, provider, algorithm);
175 }
176 catch (InvocationTargetException x)
177 {
178 cause = x.getCause();
179 if (cause instanceof NoSuchAlgorithmException)
180 throw (NoSuchAlgorithmException) cause;
181 if (cause == null)
182 cause = x;
183 }
184 catch (ClassCastException x)
185 {
186 cause = x;
187 }
188 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
189 x.initCause(cause);
190 throw x;
191 }
192
193 /**
194 * Generate a secret key from a key specification, if possible.
195 *
196 * @param keySpec The key specification.
197 * @return The secret key.
198 * @throws java.security.InvalidKeySpecException If the key specification
199 * cannot be transformed into a secret key.
200 */
201 public final SecretKey generateSecret(KeySpec keySpec)
202 throws InvalidKeySpecException
203 {
204 return skfSpi.engineGenerateSecret(keySpec);
205 }
206
207 /**
208 * Get the algorithm name.
209 *
210 * @return The algorithm name.
211 */
212 public final String getAlgorithm()
213 {
214 return algorithm;
215 }
216
217 /**
218 * Get the key specification from a secret key.
219 *
220 * @param key The secret key.
221 * @param keySpec The target key specification class.
222 * @return The key specification.
223 * @throws java.security.spec.InvalidKeySpecException If the secret key cannot
224 * be transformed into the specified key specification.
225 */
226 public final KeySpec getKeySpec(SecretKey key, Class keySpec)
227 throws InvalidKeySpecException
228 {
229 return skfSpi.engineGetKeySpec(key, keySpec);
230 }
231
232 /**
233 * Get the provider of this implementation.
234 *
235 * @return The provider.
236 */
237 public final Provider getProvider()
238 {
239 return provider;
240 }
241
242 /**
243 * Translate a secret key into another form.
244 *
245 * @param key The key to translate.
246 * @return The translated key.
247 * @throws java.security.InvalidKeyException If the argument cannot be
248 * translated.
249 */
250 public final SecretKey translateKey(SecretKey key)
251 throws InvalidKeyException
252 {
253 return skfSpi.engineTranslateKey(key);
254 }
255 }