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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.shiro.crypto;
20  
21  /**
22   * {@code CipherService} using the {@code Blowfish} cipher algorithm for all encryption, decryption, and key operations.
23   * <p/>
24   * The Blowfish algorithm can support key sizes between {@code 32} and {@code 448} bits<b>*</b>, inclusive.  However,
25   * modern cryptanalysis techniques render keys of 80 bits or less mostly worthless - use {@code 128} or more whenever
26   * possible.
27   * <p/>
28   * Note that this class retains the parent class's default {@link OperationMode#CBC CBC} mode of operation
29   * instead of the typical JDK default of {@link OperationMode#ECB ECB}.  {@code ECB} should not be used in
30   * security-sensitive environments because {@code ECB} does not allow for initialization vectors, which are
31   * considered necessary for strong encryption.  See the {@link DefaultBlockCipherService parent class}'s JavaDoc and the
32   * {@link JcaCipherService JcaCipherService} JavaDoc for more on why the JDK default should not be used and is not
33   * used in this implementation.
34   * <p/>
35   * <b>*</b> Generating and using Blowfish key sizes greater than 128 require installation of the
36   * <a href="http://java.sun.com/javase/downloads/index.jsp">Java Cryptography Extension (JCE) Unlimited Strength
37   * Jurisdiction Policy files</a>.
38   *
39   * @since 1.0
40   */
41  public class BlowfishCipherService extends DefaultBlockCipherService {
42  
43      private static final String ALGORITHM_NAME = "Blowfish";
44      private static final int BLOCK_SIZE = 64;
45  
46      /**
47       * Creates a new {@link CipherService} instance using the {@code Blowfish} cipher algorithm with the following
48       * important cipher default attributes:
49       * <table>
50       * <tr>
51       * <th>Attribute</th>
52       * <th>Value</th>
53       * </tr>
54       * <tr>
55       * <td>{@link #setKeySize keySize}</td>
56       * <td>{@code 128} bits</td>
57       * </tr>
58       * <tr>
59       * <td>{@link #setBlockSize blockSize}</td>
60       * <td>{@code 64} bits (required for {@code Blowfish})</td>
61       * </tr>
62       * <tr>
63       * <td>{@link #setMode mode}</td>
64       * <td>{@link OperationMode#CBC CBC}<b>*</b></td>
65       * </tr>
66       * <tr>
67       * <td>{@link #setPaddingScheme paddingScheme}</td>
68       * <td>{@link PaddingScheme#PKCS5 PKCS5}</td>
69       * </tr>
70       * <tr>
71       * <td>{@link #setInitializationVectorSize(int) initializationVectorSize}</td>
72       * <td>{@code 64} bits</td>
73       * </tr>
74       * <tr>
75       * <td>{@link #setGenerateInitializationVectors(boolean) generateInitializationVectors}</td>
76       * <td>{@code true}<b>**</b></td>
77       * </tr>
78       * </table>
79       * <p/>
80       * <b>*</b> The {@link OperationMode#CBC CBC} operation mode is used instead of the JDK default {@code ECB} to
81       * ensure strong encryption.  {@code ECB} should not be used in security-sensitive environments - see the
82       * {@link DefaultBlockCipherService DefaultBlockCipherService} class JavaDoc's &quot;Operation Mode&quot; section
83       * for more.
84       * <p/>
85       * <b>**</b>In conjunction with the default {@code CBC} operation mode, initialization vectors are generated by
86       * default to ensure strong encryption.  See the {@link JcaCipherService JcaCipherService} class JavaDoc for more.
87       */
88      public BlowfishCipherService() {
89          super(ALGORITHM_NAME);
90          setInitializationVectorSize(BLOCK_SIZE); //like most block ciphers, the IV size is the same as the block size
91      }
92  }