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1   package org.apache.fulcrum.crypto.provider;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.Random;
23  
24  import org.apache.fulcrum.crypto.CryptoAlgorithm;
25  
26  /**
27   * Implements Standard Unix crypt(3) for use with the Crypto Service.
28   *
29   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
30   * @version $Id$
31   */
32  public class UnixCrypt implements CryptoAlgorithm 
33  {
34  
35  	/** The seed to use */
36  	private String seed = null;
37  
38  	/** standard Unix crypt chars (64) */
39  	private static final char[] SALT_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789./"
40  			.toCharArray();
41  
42  	/**
43  	 * Constructor
44  	 */
45  	public UnixCrypt() 
46  	{
47  	}
48  
49  	/**
50  	 * This class never uses anything but UnixCrypt, so it is just a dummy (Fixme:
51  	 * Should we throw an exception if something is requested that we don't support?
52  	 *
53  	 * @param cipher Cipher (ignored)
54  	 */
55  	public void setCipher(String cipher) 
56  	{
57  		/* dummy */
58  	}
59  
60  	/**
61  	 * Setting the seed for the UnixCrypt algorithm. If a null value is supplied, or
62  	 * no seed is set, then a random seed is used.
63  	 *
64  	 * @param seed The seed value to use.
65  	 */
66  	public void setSeed(String seed) 
67  	{
68  		this.seed = seed;
69  	}
70  
71  	/**
72  	 * Encrypt the supplied string with the requested cipher
73  	 *
74  	 * @param value The value to be encrypted
75  	 * @return The encrypted value
76  	 * @throws Exception An Exception of the underlying implementation.
77  	 */
78  	public String encrypt(String value) throws Exception 
79  	{
80  		if (seed == null) 
81  		{
82  			Random randomGenerator = new Random();
83  			int numSaltChars = SALT_CHARS.length;
84  			StringBuilder sb = new StringBuilder();
85  			sb.append(SALT_CHARS[Math.abs(randomGenerator.nextInt() % numSaltChars)])
86  					.append(SALT_CHARS[Math.abs(randomGenerator.nextInt() % numSaltChars)]).toString();
87  			seed = sb.toString();
88  		}
89  
90  		// use commons-codec to do the encryption
91  		return org.apache.commons.codec.digest.UnixCrypt.crypt(value, seed);
92  	}
93  }