1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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
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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).
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24 */
25
26package javax.crypto.spec;
27
28import java.security.InvalidKeyException;
29
30/**
31 * This class specifies a DES-EDE ("triple-DES") key.
32 *
33 * @author Jan Luehe
34 *
35 * @since 1.4
36 */
37public class DESedeKeySpec implements java.security.spec.KeySpec {
38
39    /**
40     * The constant which defines the length of a DESede key in bytes.
41     */
42    public static final int DES_EDE_KEY_LEN = 24;
43
44    private byte[] key;
45
46    /**
47     * Creates a DESedeKeySpec object using the first 24 bytes in
48     * <code>key</code> as the key material for the DES-EDE key.
49     *
50     * <p> The bytes that constitute the DES-EDE key are those between
51     * <code>key[0]</code> and <code>key[23]</code> inclusive
52     *
53     * @param key the buffer with the DES-EDE key material. The first
54     * 24 bytes of the buffer are copied to protect against subsequent
55     * modification.
56     *
57     * @exception NullPointerException if <code>key</code> is null.
58     * @exception InvalidKeyException if the given key material is shorter
59     * than 24 bytes.
60     */
61    public DESedeKeySpec(byte[] key) throws InvalidKeyException {
62        this(key, 0);
63    }
64
65    /**
66     * Creates a DESedeKeySpec object using the first 24 bytes in
67     * <code>key</code>, beginning at <code>offset</code> inclusive,
68     * as the key material for the DES-EDE key.
69     *
70     * <p> The bytes that constitute the DES-EDE key are those between
71     * <code>key[offset]</code> and <code>key[offset+23]</code> inclusive.
72     *
73     * @param key the buffer with the DES-EDE key material. The first
74     * 24 bytes of the buffer beginning at <code>offset</code> inclusive
75     * are copied to protect against subsequent modification.
76     * @param offset the offset in <code>key</code>, where the DES-EDE key
77     * material starts.
78     *
79     * @exception NullPointerException if <code>key</code> is null.
80     * @exception InvalidKeyException if the given key material, starting at
81     * <code>offset</code> inclusive, is shorter than 24 bytes
82     */
83    public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException {
84        if (key.length - offset < 24) {
85            throw new InvalidKeyException("Wrong key size");
86        }
87        this.key = new byte[24];
88        System.arraycopy(key, offset, this.key, 0, 24);
89    }
90
91    /**
92     * Returns the DES-EDE key.
93     *
94     * @return the DES-EDE key. Returns a new array
95     * each time this method is called.
96     */
97    public byte[] getKey() {
98        return this.key.clone();
99    }
100
101    /**
102     * Checks if the given DES-EDE key, starting at <code>offset</code>
103     * inclusive, is parity-adjusted.
104     *
105     * @param key    a byte array which holds the key value
106     * @param offset the offset into the byte array
107     * @return true if the given DES-EDE key is parity-adjusted, false
108     * otherwise
109     *
110     * @exception NullPointerException if <code>key</code> is null.
111     * @exception InvalidKeyException if the given key material, starting at
112     * <code>offset</code> inclusive, is shorter than 24 bytes
113     */
114    public static boolean isParityAdjusted(byte[] key, int offset)
115        throws InvalidKeyException {
116            if (key.length - offset < 24) {
117                throw new InvalidKeyException("Wrong key size");
118            }
119            if (DESKeySpec.isParityAdjusted(key, offset) == false
120                || DESKeySpec.isParityAdjusted(key, offset + 8) == false
121                || DESKeySpec.isParityAdjusted(key, offset + 16) == false) {
122                return false;
123            }
124            return true;
125    }
126}
127