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1   /*
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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
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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
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19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24   */
25  
26  package javax.crypto.spec;
27  
28  import java.security.spec.AlgorithmParameterSpec;
29  
30  /**
31   * This class specifies the parameters used with the
32   * <a href="http://www.ietf.org/rfc/rfc2268.txt"><i>RC2</i></a>
33   * algorithm.
34   *
35   * <p> The parameters consist of an effective key size and optionally
36   * an 8-byte initialization vector (IV) (only in feedback mode).
37   *
38   * <p> This class can be used to initialize a <code>Cipher</code> object that
39   * implements the <i>RC2</i> algorithm.
40   *
41   * @author Jan Luehe
42   *
43   * @since 1.4
44   */
45  public class RC2ParameterSpec implements AlgorithmParameterSpec {
46  
47      private byte[] iv = null;
48      private int effectiveKeyBits;
49  
50      /**
51       * Constructs a parameter set for RC2 from the given effective key size
52       * (in bits).
53       *
54       * @param effectiveKeyBits the effective key size in bits.
55       */
56      public RC2ParameterSpec(int effectiveKeyBits) {
57          this.effectiveKeyBits = effectiveKeyBits;
58      }
59  
60      /**
61       * Constructs a parameter set for RC2 from the given effective key size
62       * (in bits) and an 8-byte IV.
63       *
64       * <p> The bytes that constitute the IV are those between
65       * <code>iv[0]</code> and <code>iv[7]</code> inclusive.
66       *
67       * @param effectiveKeyBits the effective key size in bits.
68       * @param iv the buffer with the 8-byte IV. The first 8 bytes of
69       * the buffer are copied to protect against subsequent modification.
70       * @exception IllegalArgumentException if <code>iv</code> is null.
71       */
72      public RC2ParameterSpec(int effectiveKeyBits, byte[] iv) {
73          this(effectiveKeyBits, iv, 0);
74      }
75  
76      /**
77       * Constructs a parameter set for RC2 from the given effective key size
78       * (in bits) and IV.
79       *
80       * <p> The IV is taken from <code>iv</code>, starting at
81       * <code>offset</code> inclusive.
82       * The bytes that constitute the IV are those between
83       * <code>iv[offset]</code> and <code>iv[offset+7]</code> inclusive.
84       *
85       * @param effectiveKeyBits the effective key size in bits.
86       * @param iv the buffer with the IV. The first 8 bytes
87       * of the buffer beginning at <code>offset</code> inclusive
88       * are copied to protect against subsequent modification.
89       * @param offset the offset in <code>iv</code> where the 8-byte IV
90       * starts.
91       * @exception IllegalArgumentException if <code>iv</code> is null.
92       */
93      public RC2ParameterSpec(int effectiveKeyBits, byte[] iv, int offset) {
94          this.effectiveKeyBits = effectiveKeyBits;
95          if (iv == null) throw new IllegalArgumentException("IV missing");
96          int blockSize = 8;
97          if (iv.length - offset < blockSize) {
98              throw new IllegalArgumentException("IV too short");
99          }
100         this.iv = new byte[blockSize];
101         System.arraycopy(iv, offset, this.iv, 0, blockSize);
102     }
103 
104     /**
105      * Returns the effective key size in bits.
106      *
107      * @return the effective key size in bits.
108      */
109     public int getEffectiveKeyBits() {
110         return this.effectiveKeyBits;
111     }
112 
113     /**
114      * Returns the IV or null if this parameter set does not contain an IV.
115      *
116      * @return the IV or null if this parameter set does not contain an IV.
117      * Returns a new array each time this method is called.
118      */
119     public byte[] getIV() {
120         return (iv == null? null:iv.clone());
121     }
122 
123    /**
124      * Tests for equality between the specified object and this
125      * object. Two RC2ParameterSpec objects are considered equal if their
126      * effective key sizes and IVs are equal.
127      * (Two IV references are considered equal if both are <tt>null</tt>.)
128      *
129      * @param obj the object to test for equality with this object.
130      *
131      * @return true if the objects are considered equal, false if
132      * <code>obj</code> is null or otherwise.
133      */
134     public boolean equals(Object obj) {
135         if (obj == this) {
136             return true;
137         }
138         if (!(obj instanceof RC2ParameterSpec)) {
139             return false;
140         }
141         RC2ParameterSpec other = (RC2ParameterSpec) obj;
142 
143         return ((effectiveKeyBits == other.effectiveKeyBits) &&
144                 java.util.Arrays.equals(iv, other.iv));
145     }
146 
147     /**
148      * Calculates a hash code value for the object.
149      * Objects that are equal will also have the same hashcode.
150      */
151     public int hashCode() {
152         int retval = 0;
153         if (iv != null) {
154             for (int i = 1; i < iv.length; i++) {
155                 retval += iv[i] * i;
156             }
157         }
158         return (retval += effectiveKeyBits);
159     }
160 }