Source for java.security.KeyPairGenerator

   1: /* KeyPairGenerator.java --- Key Pair Generator Class
   2:    Copyright (C) 1999, 2002, 2003, 2004, 2005  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 java.security;
  40: 
  41: import gnu.java.security.Engine;
  42: 
  43: import java.lang.reflect.InvocationTargetException;
  44: import java.security.spec.AlgorithmParameterSpec;
  45: 
  46: /**
  47:  * <code>KeyPairGenerator</code> is a class used to generate key-pairs for a
  48:  * security algorithm.
  49:  * 
  50:  * <p>The <code>KeyPairGenerator</code> is created with the
  51:  * <code>getInstance()</code> Factory methods. It is used to generate a pair of
  52:  * public and private keys for a specific algorithm and associate this key-pair
  53:  * with the algorithm parameters it was initialized with.</p>
  54:  *
  55:  * @see KeyPair
  56:  * @see AlgorithmParameterSpec
  57:  * @author Mark Benvenuto
  58:  * @author Casey Marshall
  59:  */
  60: public abstract class KeyPairGenerator extends KeyPairGeneratorSpi
  61: {
  62:   /** The service name for key pair generators. */
  63:   private static final String KEY_PAIR_GENERATOR = "KeyPairGenerator";
  64: 
  65:   Provider provider;
  66:   private String algorithm;
  67: 
  68:   /**
  69:    * Constructs a new instance of <code>KeyPairGenerator</code>.
  70:    * 
  71:    * @param algorithm
  72:    *          the algorithm to use.
  73:    */
  74:   protected KeyPairGenerator(String algorithm)
  75:   {
  76:     this.algorithm = algorithm;
  77:     this.provider = null;
  78:   }
  79: 
  80:   /**
  81:    * Returns the name of the algorithm used.
  82:    * 
  83:    * @return the name of the algorithm used.
  84:    */
  85:   public String getAlgorithm()
  86:   {
  87:     return algorithm;
  88:   }
  89: 
  90:   /**
  91:    * Returns a new instance of <code>KeyPairGenerator</code> which generates
  92:    * key-pairs for the specified algorithm.
  93:    * 
  94:    * @param algorithm the name of the algorithm to use.
  95:    * @return a new instance repesenting the desired algorithm.
  96:    * @throws NoSuchAlgorithmException if the algorithm is not implemented by any
  97:    *           provider.
  98:    * @throws IllegalArgumentException if <code>algorithm</code> is
  99:    *           <code>null</code> or is an empty string.
 100:    */
 101:   public static KeyPairGenerator getInstance(String algorithm)
 102:       throws NoSuchAlgorithmException
 103:   {
 104:     Provider[] p = Security.getProviders();
 105:     NoSuchAlgorithmException lastException = null;
 106:     for (int i = 0; i < p.length; i++)
 107:       try
 108:         {
 109:           return getInstance(algorithm, p[i]);
 110:         }
 111:       catch (NoSuchAlgorithmException x)
 112:         {
 113:           lastException = x;
 114:         }
 115:     if (lastException != null)
 116:       throw lastException;
 117:     throw new NoSuchAlgorithmException(algorithm);
 118:   }
 119: 
 120:   /**
 121:    * Returns a new instance of <code>KeyPairGenerator</code> which generates
 122:    * key-pairs for the specified algorithm from a named provider.
 123:    * 
 124:    * @param algorithm the name of the algorithm to use.
 125:    * @param provider the name of a {@link Provider} to use.
 126:    * @return a new instance repesenting the desired algorithm.
 127:    * @throws NoSuchAlgorithmException if the algorithm is not implemented by the
 128:    *           named provider.
 129:    * @throws NoSuchProviderException if the named provider was not found.
 130:    * @throws IllegalArgumentException if either <code>algorithm</code> or
 131:    *           <code>provider</code> is <code>null</code> or empty.
 132:    */
 133:   public static KeyPairGenerator getInstance(String algorithm, String provider)
 134:       throws NoSuchAlgorithmException, NoSuchProviderException
 135:   {
 136:     if (provider == null)
 137:       throw new IllegalArgumentException("provider MUST NOT be null");
 138:     provider = provider.trim();
 139:     if (provider.length() == 0)
 140:       throw new IllegalArgumentException("provider MUST NOT be empty");
 141:     Provider p = Security.getProvider(provider);
 142:     if (p == null)
 143:       throw new NoSuchProviderException(provider);
 144:     return getInstance(algorithm, p);
 145:   }
 146: 
 147:   /**
 148:    * Returns a new instance of <code>KeyPairGenerator</code> which generates
 149:    * key-pairs for the specified algorithm from a designated {@link Provider}.
 150:    * 
 151:    * @param algorithm
 152:    *          the name of the algorithm to use.
 153:    * @param provider
 154:    *          the {@link Provider} to use.
 155:    * @return a new insatnce repesenting the desired algorithm.
 156:    * @throws NoSuchAlgorithmException
 157:    *           if the algorithm is not implemented by the {@link Provider}.
 158:    * @throws IllegalArgumentException if either <code>algorithm</code> or
 159:    *           <code>provider</code> is <code>null</code>, or if
 160:    *           <code>algorithm</code> is an empty string.
 161:    * @since 1.4
 162:    * @see Provider
 163:    */
 164:   public static KeyPairGenerator getInstance(String algorithm, 
 165:                          Provider provider)
 166:     throws NoSuchAlgorithmException
 167:   {
 168:     StringBuilder sb = new StringBuilder("KeyPairGenerator for algorithm [")
 169:         .append(algorithm).append("] from provider[")
 170:         .append(provider).append("] ");
 171:     Object o;
 172:     try
 173:       {
 174:         o = Engine.getInstance(KEY_PAIR_GENERATOR, algorithm, provider);
 175:       }
 176:     catch (InvocationTargetException x)
 177:       {
 178:         Throwable cause = x.getCause();
 179:         if (cause instanceof NoSuchAlgorithmException)
 180:           throw (NoSuchAlgorithmException) cause;
 181:         if (cause == null)
 182:           cause = x;
 183:         sb.append("could not be created");
 184:         NoSuchAlgorithmException y = new NoSuchAlgorithmException(sb.toString());
 185:         y.initCause(cause);
 186:         throw y;
 187:       }
 188:     KeyPairGenerator result;
 189:     if (o instanceof KeyPairGenerator)
 190:       {
 191:         result = (KeyPairGenerator) o;
 192:         result.algorithm = algorithm;
 193:       }
 194:     else if (o instanceof KeyPairGeneratorSpi)
 195:       result = new DummyKeyPairGenerator((KeyPairGeneratorSpi) o, algorithm);
 196:     else
 197:       {
 198:         sb.append("is of an unexpected Type: ").append(o.getClass().getName());
 199:         throw new NoSuchAlgorithmException(sb.toString());
 200:       }
 201:     result.provider = provider;
 202:     return result;
 203:   }
 204: 
 205:   /**
 206:    * Returns the {@link Provider} of this instance.
 207:    * 
 208:    * @return the {@link Provider} of this instance.
 209:    */
 210:   public final Provider getProvider()
 211:   {
 212:     return provider;
 213:   }
 214: 
 215:   /**
 216:    * Initializes this instance for the specified key size. Since no source of
 217:    * randomness is specified, a default one will be used.
 218:    * 
 219:    * @param keysize
 220:    *          the size of keys to use.
 221:    */
 222:   public void initialize(int keysize)
 223:   {
 224:     initialize(keysize, new SecureRandom());
 225:   }
 226: 
 227:   /**
 228:    * Initializes this instance for the specified key size and
 229:    * {@link SecureRandom}.
 230:    * 
 231:    * @param keysize
 232:    *          the size of keys to use.
 233:    * @param random
 234:    *          the {@link SecureRandom} to use.
 235:    * @since 1.2
 236:    */
 237:   public void initialize(int keysize, SecureRandom random)
 238:   {
 239:   }
 240: 
 241:   /**
 242:    * Initializes this instance with the specified
 243:    * {@link AlgorithmParameterSpec}. Since no source of randomness is specified,
 244:    * a default one will be used.
 245:    * 
 246:    * @param params
 247:    *          the {@link AlgorithmParameterSpec} to use.
 248:    * @throws InvalidAlgorithmParameterException
 249:    *           if the designated specifications are invalid.
 250:    * @since 1.2
 251:    */
 252:   public void initialize(AlgorithmParameterSpec params)
 253:     throws InvalidAlgorithmParameterException
 254:   {
 255:     initialize(params, new SecureRandom());
 256:   }
 257: 
 258:   /**
 259:    * Initializes this instance with the specified {@link AlgorithmParameterSpec}
 260:    * and {@link SecureRandom}.
 261:    * 
 262:    * @param params
 263:    *          the {@link AlgorithmParameterSpec} to use.
 264:    * @param random
 265:    *          the {@link SecureRandom} to use.
 266:    * @throws InvalidAlgorithmParameterException
 267:    *           if the designated specifications are invalid.
 268:    * @since 1.2
 269:    */
 270:   public void initialize(AlgorithmParameterSpec params, SecureRandom random)
 271:     throws InvalidAlgorithmParameterException
 272:   {
 273:     super.initialize(params, random);
 274:   }
 275: 
 276:   /**
 277:    * Generates a new "DSA" {@link KeyPair} from the "GNU" security provider.
 278:    * 
 279:    * <p>This method generates a unique key-pair each time it is called.</p>
 280:    * 
 281:    * @return a new unique {@link KeyPair}.
 282:    * @see #generateKeyPair()
 283:    * @since 1.2
 284:    */
 285:   public final KeyPair genKeyPair()
 286:   {
 287:     try
 288:       {
 289:         return getInstance("DSA", "GNU").generateKeyPair();
 290:       }
 291:     catch (Exception e)
 292:       {
 293:         System.err.println("genKeyPair failed: " + e);
 294:         e.printStackTrace();
 295:         return null;
 296:       }
 297:   }
 298: 
 299:   /**
 300:    * Generates a new "DSA" {@link KeyPair} from the "GNU" security provider.
 301:    * 
 302:    * <p>This method generates a unique key pair each time it is called.</p>
 303:    * 
 304:    * @return a new unique {@link KeyPair}.
 305:    * @see #genKeyPair()
 306:    */
 307:   public KeyPair generateKeyPair()
 308:   {
 309:     return genKeyPair();
 310:   }
 311: }