Save This Page
Home » openjdk-7 » com.sun.crypto » provider » [javadoc | source]
    1   /*
    2    * Copyright (c) 2002, 2009, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package com.sun.crypto.provider;
   27   
   28   import java.security.SecureRandom;
   29   import java.security.InvalidParameterException;
   30   import java.security.InvalidAlgorithmParameterException;
   31   import java.security.InvalidKeyException;
   32   import java.security.spec.AlgorithmParameterSpec;
   33   import javax.crypto.KeyGeneratorSpi;
   34   import javax.crypto.SecretKey;
   35   import javax.crypto.spec.SecretKeySpec;
   36   
   37   
   38   /**
   39    * This class generates a AES key.
   40    *
   41    * @author Valerie Peng
   42    *
   43    */
   44   
   45   public final class AESKeyGenerator extends KeyGeneratorSpi {
   46   
   47       private SecureRandom random = null;
   48       private int keySize = 16; // default keysize (in number of bytes)
   49   
   50       /**
   51        * Empty constructor.
   52        */
   53       public AESKeyGenerator() {
   54       }
   55   
   56       /**
   57        * Initializes this key generator.
   58        *
   59        * @param random the source of randomness for this generator
   60        */
   61       protected void engineInit(SecureRandom random) {
   62           this.random = random;
   63       }
   64   
   65       /**
   66        * Initializes this key generator with the specified parameter
   67        * set and a user-provided source of randomness.
   68        *
   69        * @param params the key generation parameters
   70        * @param random the source of randomness for this key generator
   71        *
   72        * @exception InvalidAlgorithmParameterException if <code>params</code> is
   73        * inappropriate for this key generator
   74        */
   75       protected void engineInit(AlgorithmParameterSpec params,
   76                                 SecureRandom random)
   77           throws InvalidAlgorithmParameterException {
   78               throw new InvalidAlgorithmParameterException
   79                   ("AES key generation does not take any parameters");
   80       }
   81   
   82       /**
   83        * Initializes this key generator for a certain keysize, using the given
   84        * source of randomness.
   85        *
   86        * @param keysize the keysize. This is an algorithm-specific
   87        * metric specified in number of bits.
   88        * @param random the source of randomness for this key generator
   89        */
   90       protected void engineInit(int keysize, SecureRandom random) {
   91           if (((keysize % 8) != 0) ||
   92               (!AESCrypt.isKeySizeValid(keysize/8))) {
   93               throw new InvalidParameterException
   94                   ("Wrong keysize: must be equal to 128, 192 or 256");
   95           }
   96           this.keySize = keysize/8;
   97           this.engineInit(random);
   98       }
   99   
  100       /**
  101        * Generates the AES key.
  102        *
  103        * @return the new AES key
  104        */
  105       protected SecretKey engineGenerateKey() {
  106           SecretKeySpec aesKey = null;
  107   
  108           if (this.random == null) {
  109               this.random = SunJCE.RANDOM;
  110           }
  111   
  112           byte[] keyBytes = new byte[keySize];
  113           this.random.nextBytes(keyBytes);
  114           aesKey = new SecretKeySpec(keyBytes, "AES");
  115           return aesKey;
  116       }
  117   }

Save This Page
Home » openjdk-7 » com.sun.crypto » provider » [javadoc | source]