1 /*

     2  * Copyright (c) 1997, 2013, 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 javax.crypto.KeyGeneratorSpi;

    29 import javax.crypto.SecretKey;

    30 import javax.crypto.spec.DESedeKeySpec;

    31 import java.security.SecureRandom;

    32 import java.security.InvalidParameterException;

    33 import java.security.InvalidAlgorithmParameterException;

    34 import java.security.InvalidKeyException;

    35 import java.security.spec.AlgorithmParameterSpec;

    36 

    37 /**

    38  * This class generates a Triple DES key.

    39  *

    40  * @author Jan Luehe

    41  *

    42  */

    43 

    44 public final class DESedeKeyGenerator extends KeyGeneratorSpi {

    45 

    46     private SecureRandom random = null;

    47     private int keysize = 168;

    48 

    49     /**

    50      * Empty constructor

    51      */

    52     public DESedeKeyGenerator() {

    53     }

    54 

    55     /**

    56      * Initializes this key generator.

    57      *

    58      * @param random the source of randomness for this generator

    59      */

    60     protected void engineInit(SecureRandom random) {

    61         this.random = random;

    62     }

    63 

    64     /**

    65      * Initializes this key generator with the specified parameter

    66      * set and a user-provided source of randomness.

    67      *

    68      * @param params the key generation parameters

    69      * @param random the source of randomness for this key generator

    70      *

    71      * @exception InvalidAlgorithmParameterException if <code>params</code> is

    72      * inappropriate for this key generator

    73      */

    74     protected void engineInit(AlgorithmParameterSpec params,

    75                               SecureRandom random)

    76         throws InvalidAlgorithmParameterException {

    77             throw new InvalidAlgorithmParameterException

    78                 ("Triple DES key generation does not take any parameters");

    79     }

    80 

    81     /**

    82      * Initializes this key generator for a certain keysize, using the given

    83      * source of randomness.

    84      *

    85      * @param keysize the keysize. This is an algorithm-specific

    86      * metric specified in number of bits. A keysize with 112 bits of entropy

    87      * corresponds to a Triple DES key with 2 intermediate keys, and a keysize

    88      * with 168 bits of entropy corresponds to a Triple DES key with 3

    89      * intermediate keys.

    90      * @param random the source of randomness for this key generator

    91      */

    92     protected void engineInit(int keysize, SecureRandom random) {

    93         if ((keysize != 112) && (keysize != 168)) {

    94             throw new InvalidParameterException("Wrong keysize: must be "

    95                                                 + "equal to 112 or 168");

    96         }

    97         this.keysize = keysize;

    98         this.engineInit(random);

    99     }

   100 

   101     /**

   102      * Generates the Triple DES key.

   103      *

   104      * @return the new Triple DES key

   105      */

   106     protected SecretKey engineGenerateKey() {

   107         if (this.random == null) {

   108             this.random = SunJCE.getRandom();

   109         }

   110 

   111         byte[] rawkey = new byte[DESedeKeySpec.DES_EDE_KEY_LEN];

   112 

   113         if (keysize == 168) {

   114             // 3 intermediate keys

   115             this.random.nextBytes(rawkey);

   116 

   117             // Do parity adjustment for each intermediate key

   118             DESKeyGenerator.setParityBit(rawkey, 0);

   119             DESKeyGenerator.setParityBit(rawkey, 8);

   120             DESKeyGenerator.setParityBit(rawkey, 16);

   121         } else {

   122             // 2 intermediate keys

   123             byte[] tmpkey = new byte[16];

   124             this.random.nextBytes(tmpkey);

   125             DESKeyGenerator.setParityBit(tmpkey, 0);

   126             DESKeyGenerator.setParityBit(tmpkey, 8);

   127             System.arraycopy(tmpkey, 0, rawkey, 0, tmpkey.length);

   128             // Copy the first 8 bytes into the last

   129             System.arraycopy(tmpkey, 0, rawkey, 16, 8);

   130             java.util.Arrays.fill(tmpkey, (byte)0x00);

   131         }

   132 

   133         DESedeKey desEdeKey = null;

   134         try {

   135             desEdeKey = new DESedeKey(rawkey);

   136         } catch (InvalidKeyException ike) {

   137             // this never happens

   138             throw new RuntimeException(ike.getMessage());

   139         }

   140 

   141         java.util.Arrays.fill(rawkey, (byte)0x00);

   142 

   143         return desEdeKey;

   144     }

   145 }