Source for javax.crypto.KeyGenerator

   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:         KeyGenerator instance = new KeyGenerator((KeyGeneratorSpi)
 164:           Engine.getInstance(SERVICE, algorithm, provider),
 165:           provider, algorithm);
 166:         instance.init(new SecureRandom());
 167:         return instance;
 168:       }
 169:     catch (InvocationTargetException ite)
 170:       {
 171:         if (ite.getCause() == null)
 172:           throw new NoSuchAlgorithmException(algorithm);
 173:         if (ite.getCause() instanceof NoSuchAlgorithmException)
 174:           throw (NoSuchAlgorithmException) ite.getCause();
 175:         throw new NoSuchAlgorithmException(algorithm);
 176:       }
 177:     catch (ClassCastException cce)
 178:       {
 179:         throw new NoSuchAlgorithmException(algorithm);
 180:       }
 181:   }
 182: 
 183:   // Instance methods.
 184:   // ------------------------------------------------------------------------
 185: 
 186:   /**
 187:    * Generate a key.
 188:    *
 189:    * @return The new key.
 190:    */
 191:   public final SecretKey generateKey()
 192:   {
 193:     return kgSpi.engineGenerateKey();
 194:   }
 195: 
 196:   /**
 197:    * Return the name of this key generator.
 198:    *
 199:    * @return The algorithm name.
 200:    */
 201:   public final String getAlgorithm()
 202:   {
 203:     return algorithm;
 204:   }
 205: 
 206:   /**
 207:    * Return the provider of the underlying implementation.
 208:    *
 209:    * @return The provider.
 210:    */
 211:   public final Provider getProvider()
 212:   {
 213:     return provider;
 214:   }
 215: 
 216:   /**
 217:    * Initialize this key generator with a set of parameters; the
 218:    * highest-priority {@link java.security.SecureRandom} implementation
 219:    * will be used.
 220:    *
 221:    * @param params The algorithm parameters.
 222:    * @throws java.security.InvalidAlgorithmParameterException If the
 223:    *         supplied parameters are inapproprate.
 224:    */
 225:   public final void init(AlgorithmParameterSpec params)
 226:     throws InvalidAlgorithmParameterException
 227:   {
 228:     init(params, new SecureRandom());
 229:   }
 230: 
 231:   /**
 232:    * Initialize this key generator with a set of parameters and a source
 233:    * of randomness.
 234:    *
 235:    * @param params The algorithm parameters.
 236:    * @param random The source of randomness.
 237:    * @throws java.security.InvalidAlgorithmParameterException If the
 238:    *         supplied parameters are inapproprate.
 239:    */
 240:   public final void init(AlgorithmParameterSpec params, SecureRandom random)
 241:     throws InvalidAlgorithmParameterException
 242:   {
 243:     kgSpi.engineInit(params, random);
 244:   }
 245: 
 246:   /**
 247:    * Initialize this key generator with a key size (in bits); the
 248:    * highest-priority {@link java.security.SecureRandom} implementation
 249:    * will be used.
 250:    *
 251:    * @param keySize The target key size, in bits.
 252:    * @throws java.security.InvalidParameterException If the
 253:    *         key size is unsupported.
 254:    */
 255:   public final void init(int keySize)
 256:   {
 257:     init(keySize, new SecureRandom());
 258:   }
 259: 
 260:   /**
 261:    * Initialize this key generator with a key size (in bits) and a
 262:    * source of randomness.
 263:    *
 264:    * @param keySize The target key size, in bits.
 265:    * @param random  The source of randomness.
 266:    * @throws java.security.InvalidAlgorithmParameterException If the
 267:    *         key size is unsupported.
 268:    */
 269:   public final void init(int keySize, SecureRandom random)
 270:   {
 271:     kgSpi.engineInit(keySize, random);
 272:   }
 273: 
 274:   /**
 275:    * Initialize this key generator with a source of randomness. The
 276:    * implementation-specific default parameters (such as key size) will
 277:    * be used.
 278:    *
 279:    * @param random The source of randomness.
 280:    */
 281:   public final void init(SecureRandom random)
 282:   {
 283:     kgSpi.engineInit(random);
 284:   }
 285: }