gomp-20050608-branch/libjava/classpath/javax/crypto/KeyGenerator.java

   1 /* KeyGenerator.java -- Interface to a symmetric key generator.
   2    Copyright (C) 2004  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.crypto;
  40
  41 import gnu.java.security.Engine;
  42
  43 import java.lang.reflect.InvocationTargetException;
  44 import java.security.InvalidAlgorithmParameterException;
  45 import java.security.NoSuchAlgorithmException;
  46 import java.security.NoSuchProviderException;
  47 import java.security.Provider;
  48 import java.security.SecureRandom;
  49 import java.security.Security;
  50 import java.security.spec.AlgorithmParameterSpec;
  51
  52 /**
  53  * A generic producer of keys for symmetric cryptography. The keys
  54  * returned may be simple wrappers around byte arrays, or, if the
  55  * target cipher requires them, more complex objects.
  56  *
  57  * @author Casey Marshall (csm@gnu.org)
  58  * @since 1.4
  59  * @see Cipher
  60  * @see Mac
  61  */
  62 public class KeyGenerator
  63 {
  64
  65   // Constants and fields.
  66   // ------------------------------------------------------------------------
  67
  68   private static final String SERVICE = "KeyGenerator";
  69
  70   /** The underlying generator implementation. */
  71   private KeyGeneratorSpi kgSpi;
  72
  73   /** The provider of the implementation. */
  74   private Provider provider;
  75
  76   /** The name of the algorithm. */
  77   private String algorithm;
  78
  79   // Constructor.
  80   // ------------------------------------------------------------------------
  81
  82   /**
  83    * Create a new key generator.
  84    *
  85    * @param kgSpi     The underlying generator.
  86    * @param provider  The provider of this implementation.
  87    * @param algorithm The algorithm's name.
  88    */
  89   protected KeyGenerator(KeyGeneratorSpi kgSpi, Provider provider,
  90                          String algorithm)
  91   {
  92     this.kgSpi = kgSpi;
  93     this.provider = provider;
  94     this.algorithm = algorithm;
  95   }
  96
  97   // Class methods.
  98   // ------------------------------------------------------------------------
  99
 100   /**
 101    * Create a new key generator, returning the first available
 102    * implementation.
 103    *
 104    * @param algorithm The generator algorithm name.
 105    * @throws java.security.NoSuchAlgorithmException If the specified
 106    *         algorithm does not exist.
 107    */
 108   public static final KeyGenerator getInstance(String algorithm)
 109     throws NoSuchAlgorithmException
 110   {
 111     Provider[] provs = Security.getProviders();
 112     String msg = algorithm;
 113     for (int i = 0; i < provs.length; i++)
 114       {
 115         try
 116           {
 117             return getInstance(algorithm, provs[i]);
 118           }
 119         catch (NoSuchAlgorithmException nsae)
 120           {
 121             msg = nsae.getMessage();
 122           }
 123       }
 124     throw new NoSuchAlgorithmException(msg);
 125   }
 126
 127   /**
 128    * Create a new key generator from the named provider.
 129    *
 130    * @param algorithm The generator algorithm name.
 131    * @param provider  The name of the provider to use.
 132    * @return An appropriate key generator, if found.
 133    * @throws java.security.NoSuchAlgorithmException If the specified
 134    *         algorithm is not implemented by the named provider.
 135    * @throws java.security.NoSuchProviderException If the named provider
 136    *         does not exist.
 137    */
 138   public static final KeyGenerator getInstance(String algorithm, String provider)
 139     throws NoSuchAlgorithmException, NoSuchProviderException
 140   {
 141     Provider p = Security.getProvider(provider);
 142     if (p == null)
 143       {
 144         throw new NoSuchProviderException(provider);
 145       }
 146     return getInstance(algorithm, p);
 147   }
 148
 149   /**
 150    * Create a new key generator from the supplied provider.
 151    *
 152    * @param algorithm The generator algorithm name.
 153    * @param provider  The provider to use.
 154    * @return An appropriate key generator, if found.
 155    * @throws java.security.NoSuchAlgorithmException If the specified
 156    *         algorithm is not implemented by the provider.
 157    */
 158   public static final KeyGenerator getInstance(String algorithm, Provider provider)
 159     throws NoSuchAlgorithmException
 160   {
 161     try
 162       {
 163         return new KeyGenerator((KeyGeneratorSpi)
 164           Engine.getInstance(SERVICE, algorithm, provider),
 165           provider, algorithm);
 166       }
 167     catch (InvocationTargetException ite)
 168       {
 169         if (ite.getCause() == null)
 170           throw new NoSuchAlgorithmException(algorithm);
 171         if (ite.getCause() instanceof NoSuchAlgorithmException)
 172           throw (NoSuchAlgorithmException) ite.getCause();
 173         throw new NoSuchAlgorithmException(algorithm);
 174       }
 175     catch (ClassCastException cce)
 176       {
 177         throw new NoSuchAlgorithmException(algorithm);
 178       }
 179   }
 180
 181   // Instance methods.
 182   // ------------------------------------------------------------------------
 183
 184   /**
 185    * Generate a key.
 186    *
 187    * @return The new key.
 188    */
 189   public final SecretKey generateKey()
 190   {
 191     return kgSpi.engineGenerateKey();
 192   }
 193
 194   /**
 195    * Return the name of this key generator.
 196    *
 197    * @return The algorithm name.
 198    */
 199   public final String getAlgorithm()
 200   {
 201     return algorithm;
 202   }
 203
 204   /**
 205    * Return the provider of the underlying implementation.
 206    *
 207    * @return The provider.
 208    */
 209   public final Provider getProvider()
 210   {
 211     return provider;
 212   }
 213
 214   /**
 215    * Initialize this key generator with a set of parameters; the
 216    * highest-priority {@link java.security.SecureRandom} implementation
 217    * will be used.
 218    *
 219    * @param params The algorithm parameters.
 220    * @throws java.security.InvalidAlgorithmParameterException If the
 221    *         supplied parameters are inapproprate.
 222    */
 223   public final void init(AlgorithmParameterSpec params)
 224     throws InvalidAlgorithmParameterException
 225   {
 226     init(params, new SecureRandom());
 227   }
 228
 229   /**
 230    * Initialize this key generator with a set of parameters and a source
 231    * of randomness.
 232    *
 233    * @param params The algorithm parameters.
 234    * @param random The source of randomness.
 235    * @throws java.security.InvalidAlgorithmParameterException If the
 236    *         supplied parameters are inapproprate.
 237    */
 238   public final void init(AlgorithmParameterSpec params, SecureRandom random)
 239     throws InvalidAlgorithmParameterException
 240   {
 241     kgSpi.engineInit(params, random);
 242   }
 243
 244   /**
 245    * Initialize this key generator with a key size (in bits); the
 246    * highest-priority {@link java.security.SecureRandom} implementation
 247    * will be used.
 248    *
 249    * @param keySize The target key size, in bits.
 250    * @throws java.security.InvalidParameterException If the
 251    *         key size is unsupported.
 252    */
 253   public final void init(int keySize)
 254   {
 255     init(keySize, new SecureRandom());
 256   }
 257
 258   /**
 259    * Initialize this key generator with a key size (in bits) and a
 260    * source of randomness.
 261    *
 262    * @param keySize The target key size, in bits.
 263    * @param random  The source of randomness.
 264    * @throws java.security.InvalidAlgorithmParameterException If the
 265    *         key size is unsupported.
 266    */
 267   public final void init(int keySize, SecureRandom random)
 268   {
 269     kgSpi.engineInit(keySize, random);
 270   }
 271
 272   /**
 273    * Initialize this key generator with a source of randomness. The
 274    * implementation-specific default parameters (such as key size) will
 275    * be used.
 276    *
 277    * @param random The source of randomness.
 278    */
 279   public final void init(SecureRandom random)
 280   {
 281     kgSpi.engineInit(random);
 282   }
 283 }