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
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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
26package javax.crypto.spec;
27
28import java.security.spec.AlgorithmParameterSpec;
29
30/**
31 * This class specifies an <i>initialization vector</i> (IV).
32 * Examples which use IVs are ciphers in feedback mode,
33 * e.g., DES in CBC mode and RSA ciphers with OAEP encoding
34 * operation.
35 *
36 * @author Jan Luehe
37 *
38 * @since 1.4
39 */
40public class IvParameterSpec implements AlgorithmParameterSpec {
41
42    private byte[] iv;
43
44    /**
45     * Creates an IvParameterSpec object using the bytes in <code>iv</code>
46     * as the IV.
47     *
48     * @param iv the buffer with the IV. The contents of the
49     * buffer are copied to protect against subsequent modification.
50     * @throws NullPointerException if <code>iv</code> is <code>null</code>
51     */
52    public IvParameterSpec(byte[] iv) {
53        this(iv, 0, iv.length);
54    }
55
56    /**
57     * Creates an IvParameterSpec object using the first <code>len</code>
58     * bytes in <code>iv</code>, beginning at <code>offset</code>
59     * inclusive, as the IV.
60     *
61     * <p> The bytes that constitute the IV are those between
62     * <code>iv[offset]</code> and <code>iv[offset+len-1]</code> inclusive.
63     *
64     * @param iv the buffer with the IV. The first <code>len</code>
65     * bytes of the buffer beginning at <code>offset</code> inclusive
66     * are copied to protect against subsequent modification.
67     * @param offset the offset in <code>iv</code> where the IV
68     * starts.
69     * @param len the number of IV bytes.
70     * @throws IllegalArgumentException if <code>iv</code> is <code>null</code>
71     * or {@code (iv.length - offset < len)}
72     * @throws ArrayIndexOutOfBoundsException is thrown if <code>offset</code>
73     * or <code>len</code> index bytes outside the <code>iv</code>.
74     */
75    public IvParameterSpec(byte[] iv, int offset, int len) {
76        if (iv == null) {
77            throw new IllegalArgumentException("IV missing");
78        }
79        if (iv.length - offset < len) {
80            throw new IllegalArgumentException
81                ("IV buffer too short for given offset/length combination");
82        }
83        if (len < 0) {
84            throw new ArrayIndexOutOfBoundsException("len is negative");
85        }
86        this.iv = new byte[len];
87        System.arraycopy(iv, offset, this.iv, 0, len);
88    }
89
90    /**
91     * Returns the initialization vector (IV).
92     *
93     * @return the initialization vector (IV). Returns a new array
94     * each time this method is called.
95     */
96    public byte[] getIV() {
97        return this.iv.clone();
98    }
99}
100