001 /* KeyGenerator.java -- Interface to a symmetric key generator.
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.InvalidAlgorithmParameterException;
045 import java.security.NoSuchAlgorithmException;
046 import java.security.NoSuchProviderException;
047 import java.security.Provider;
048 import java.security.SecureRandom;
049 import java.security.Security;
050 import java.security.spec.AlgorithmParameterSpec;
051
052 /**
053 * A generic producer of keys for symmetric cryptography. The keys
054 * returned may be simple wrappers around byte arrays, or, if the
055 * target cipher requires them, more complex objects.
056 *
057 * @author Casey Marshall (csm@gnu.org)
058 * @since 1.4
059 * @see Cipher
060 * @see Mac
061 */
062 public class KeyGenerator
063 {
064
065 // Constants and fields.
066 // ------------------------------------------------------------------------
067
068 private static final String SERVICE = "KeyGenerator";
069
070 /** The underlying generator implementation. */
071 private KeyGeneratorSpi kgSpi;
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 key generator.
084 *
085 * @param kgSpi The underlying generator.
086 * @param provider The provider of this implementation.
087 * @param algorithm The algorithm's name.
088 */
089 protected KeyGenerator(KeyGeneratorSpi kgSpi, Provider provider,
090 String algorithm)
091 {
092 this.kgSpi = kgSpi;
093 this.provider = provider;
094 this.algorithm = algorithm;
095 }
096
097 /**
098 * Create a new key generator, returning the first available implementation.
099 *
100 * @param algorithm The generator algorithm name.
101 * @throws NoSuchAlgorithmException If the specified algorithm does not exist.
102 * @throws IllegalArgumentException if <code>algorithm</code> is
103 * <code>null</code> or is an empty string.
104 */
105 public static final KeyGenerator getInstance(String algorithm)
106 throws NoSuchAlgorithmException
107 {
108 Provider[] p = Security.getProviders();
109 NoSuchAlgorithmException lastException = null;
110 for (int i = 0; i < p.length; i++)
111 try
112 {
113 return getInstance(algorithm, p[i]);
114 }
115 catch (NoSuchAlgorithmException x)
116 {
117 lastException = x;
118 }
119 if (lastException != null)
120 throw lastException;
121 throw new NoSuchAlgorithmException(algorithm);
122 }
123
124 /**
125 * Create a new key generator from the named provider.
126 *
127 * @param algorithm The generator algorithm name.
128 * @param provider The name of the provider to use.
129 * @return An appropriate key generator, if found.
130 * @throws NoSuchAlgorithmException If the specified algorithm is not
131 * implemented by the named provider.
132 * @throws NoSuchProviderException If the named provider does not exist.
133 * @throws IllegalArgumentException if either <code>algorithm</code> or
134 * <code>provider</code> is <code>null</code>, or if
135 * <code>algorithm</code> is an empty string.
136 */
137 public static final KeyGenerator getInstance(String algorithm, String provider)
138 throws NoSuchAlgorithmException, NoSuchProviderException
139 {
140 if (provider == null)
141 throw new IllegalArgumentException("provider MUST NOT be null");
142 Provider p = Security.getProvider(provider);
143 if (p == null)
144 throw new NoSuchProviderException(provider);
145 return getInstance(algorithm, p);
146 }
147
148 /**
149 * Create a new key generator from the supplied provider.
150 *
151 * @param algorithm The generator algorithm name.
152 * @param provider The provider to use.
153 * @return An appropriate key generator, if found.
154 * @throws NoSuchAlgorithmException If the specified algorithm is not
155 * implemented by the provider.
156 * @throws IllegalArgumentException if either <code>algorithm</code> or
157 * <code>provider</code> is <code>null</code>, or if
158 * <code>algorithm</code> is an empty string.
159 */
160 public static final KeyGenerator getInstance(String algorithm,
161 Provider provider)
162 throws NoSuchAlgorithmException
163 {
164 StringBuilder sb = new StringBuilder("KeyGenerator algorithm [")
165 .append(algorithm).append("] from provider[")
166 .append(provider).append("] could not be created");
167 Throwable cause;
168 try
169 {
170 Object spi = Engine.getInstance(SERVICE, algorithm, provider);
171 KeyGenerator instance = new KeyGenerator((KeyGeneratorSpi) spi,
172 provider,
173 algorithm);
174 instance.init(new SecureRandom());
175 return instance;
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 * Generate a key.
196 *
197 * @return The new key.
198 */
199 public final SecretKey generateKey()
200 {
201 return kgSpi.engineGenerateKey();
202 }
203
204 /**
205 * Return the name of this key generator.
206 *
207 * @return The algorithm name.
208 */
209 public final String getAlgorithm()
210 {
211 return algorithm;
212 }
213
214 /**
215 * Return the provider of the underlying implementation.
216 *
217 * @return The provider.
218 */
219 public final Provider getProvider()
220 {
221 return provider;
222 }
223
224 /**
225 * Initialize this key generator with a set of parameters; the
226 * highest-priority {@link java.security.SecureRandom} implementation
227 * will be used.
228 *
229 * @param params The algorithm parameters.
230 * @throws java.security.InvalidAlgorithmParameterException If the
231 * supplied parameters are inapproprate.
232 */
233 public final void init(AlgorithmParameterSpec params)
234 throws InvalidAlgorithmParameterException
235 {
236 init(params, new SecureRandom());
237 }
238
239 /**
240 * Initialize this key generator with a set of parameters and a source
241 * of randomness.
242 *
243 * @param params The algorithm parameters.
244 * @param random The source of randomness.
245 * @throws java.security.InvalidAlgorithmParameterException If the
246 * supplied parameters are inapproprate.
247 */
248 public final void init(AlgorithmParameterSpec params, SecureRandom random)
249 throws InvalidAlgorithmParameterException
250 {
251 kgSpi.engineInit(params, random);
252 }
253
254 /**
255 * Initialize this key generator with a key size (in bits); the
256 * highest-priority {@link java.security.SecureRandom} implementation
257 * will be used.
258 *
259 * @param keySize The target key size, in bits.
260 * @throws java.security.InvalidParameterException If the
261 * key size is unsupported.
262 */
263 public final void init(int keySize)
264 {
265 init(keySize, new SecureRandom());
266 }
267
268 /**
269 * Initialize this key generator with a key size (in bits) and a
270 * source of randomness.
271 *
272 * @param keySize The target key size, in bits.
273 * @param random The source of randomness.
274 * @throws java.security.InvalidAlgorithmParameterException If the
275 * key size is unsupported.
276 */
277 public final void init(int keySize, SecureRandom random)
278 {
279 kgSpi.engineInit(keySize, random);
280 }
281
282 /**
283 * Initialize this key generator with a source of randomness. The
284 * implementation-specific default parameters (such as key size) will
285 * be used.
286 *
287 * @param random The source of randomness.
288 */
289 public final void init(SecureRandom random)
290 {
291 kgSpi.engineInit(random);
292 }
293 }