Source for javax.crypto.SecretKeyFactory

   1: /* SecretKeyFactory.java -- Factory for creating secret keys.
   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.InvalidKeyException;
  45: import java.security.NoSuchAlgorithmException;
  46: import java.security.NoSuchProviderException;
  47: import java.security.Provider;
  48: import java.security.Security;
  49: import java.security.spec.InvalidKeySpecException;
  50: import java.security.spec.KeySpec;
  51: 
  52: /**
  53:  * A secret key factory translates {@link SecretKey} objects to and from
  54:  * {@link java.security.spec.KeySpec} objects, and can translate between
  55:  * different vendors' representations of {@link SecretKey} objects (for
  56:  * security or semantics; whichever applies).
  57:  *
  58:  * @author Casey Marshall (csm@gnu.org)
  59:  * @since 1.4
  60:  * @see SecretKey
  61:  */
  62: public class SecretKeyFactory
  63: {
  64: 
  65:   // Constants and fields.
  66:   // ------------------------------------------------------------------------
  67: 
  68:   private static final String SERVICE = "SecretKeyFactory";
  69: 
  70:   /** The underlying factory implementation. */
  71:   private SecretKeyFactorySpi skfSpi;
  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 secret key factory.
  84:    *
  85:    * @param skfSpi   The underlying factory implementation.
  86:    * @param provider The provider.
  87:    * @param algorithm The algorithm name.
  88:    */
  89:   protected SecretKeyFactory(SecretKeyFactorySpi skfSpi, Provider provider,
  90:                              String algorithm)
  91:   {
  92:     this.skfSpi = skfSpi;
  93:     this.provider = provider;
  94:     this.algorithm = algorithm;
  95:   }
  96: 
  97:   // Class methods.
  98:   // ------------------------------------------------------------------------
  99: 
 100:   /**
 101:    * Create a new secret key factory from the first appropriate
 102:    * instance.
 103:    *
 104:    * @param algorithm The algorithm name.
 105:    * @return The appropriate key factory, if found.
 106:    * @throws java.security.NoSuchAlgorithmException If no provider
 107:    *         implements the specified algorithm.
 108:    */
 109:   public static final SecretKeyFactory getInstance(String algorithm)
 110:     throws NoSuchAlgorithmException
 111:   {
 112:     Provider[] provs = Security.getProviders();
 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:           }
 122:       }
 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 java.security.NoSuchAlgorithmException If the named
 133:    *         provider does not implement the algorithm.
 134:    * @throws java.security.NoSuchProviderException If the named provider
 135:    *         does not exist.
 136:    */
 137:   public static final SecretKeyFactory getInstance(String algorithm,
 138:                                                    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 secret key factory from the specified provider.
 151:    *
 152:    * @param algorithm The algorithm name.
 153:    * @param provider  The provider.
 154:    * @return The appropriate key factory, if found.
 155:    * @throws java.security.NoSuchAlgorithmException If the provider
 156:    *         does not implement the algorithm.
 157:    */
 158:   public static final SecretKeyFactory getInstance(String algorithm,
 159:                                                    Provider provider)
 160:     throws NoSuchAlgorithmException
 161:   {
 162:     try
 163:       {
 164:         return new SecretKeyFactory((SecretKeyFactorySpi)
 165:           Engine.getInstance(SERVICE, algorithm, provider),
 166:           provider, algorithm);
 167:       }
 168:     catch (InvocationTargetException ite)
 169:       {
 170:         if (ite.getCause() == null)
 171:           throw new NoSuchAlgorithmException(algorithm);
 172:         if (ite.getCause() instanceof NoSuchAlgorithmException)
 173:           throw (NoSuchAlgorithmException) ite.getCause();
 174:         throw new NoSuchAlgorithmException(algorithm);
 175:       }
 176:     catch (ClassCastException cce)
 177:       {
 178:         throw new NoSuchAlgorithmException(algorithm);
 179:       }
 180:   }
 181: 
 182:   // Instance methods.
 183:   // ------------------------------------------------------------------------
 184: 
 185:   /**
 186:    * Generate a secret key from a key specification, if possible.
 187:    *
 188:    * @param keySpec The key specification.
 189:    * @return The secret key.
 190:    * @throws java.security.InvalidKeySpecException If the key specification
 191:    *         cannot be transformed into a secret key.
 192:    */
 193:   public final SecretKey generateSecret(KeySpec keySpec)
 194:     throws InvalidKeySpecException
 195:   {
 196:     return skfSpi.engineGenerateSecret(keySpec);
 197:   }
 198: 
 199:   /**
 200:    * Get the algorithm name.
 201:    *
 202:    * @return The algorithm name.
 203:    */
 204:   public final String getAlgorithm()
 205:   {
 206:     return algorithm;
 207:   }
 208: 
 209:   /**
 210:    * Get the key specification from a secret key.
 211:    *
 212:    * @param key     The secret key.
 213:    * @param keySpec The target key specification class.
 214:    * @return The key specification.
 215:    * @throws java.security.spec.InvalidKeySpecException If the secret key cannot
 216:    *         be transformed into the specified key specification.
 217:    */
 218:   public final KeySpec getKeySpec(SecretKey key, Class keySpec)
 219:     throws InvalidKeySpecException
 220:   {
 221:     return skfSpi.engineGetKeySpec(key, keySpec);
 222:   }
 223: 
 224:   /**
 225:    * Get the provider of this implementation.
 226:    *
 227:    * @return The provider.
 228:    */
 229:   public final Provider getProvider()
 230:   {
 231:     return provider;
 232:   }
 233: 
 234:   /**
 235:    * Translate a secret key into another form.
 236:    *
 237:    * @param key The key to translate.
 238:    * @return The translated key.
 239:    * @throws java.security.InvalidKeyException If the argument cannot be
 240:    *         translated.
 241:    */
 242:   public final SecretKey translateKey(SecretKey key)
 243:     throws InvalidKeyException
 244:   {
 245:     return skfSpi.engineTranslateKey(key);
 246:   }
 247: }