Rahul Ravikumar | 0533600 | 2019-10-14 15:04:32 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2011, 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 |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 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 |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 22 | * or visit www.oracle.com if you need additional information or have any |
| 23 | * questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.crypto.spec; |
| 27 | |
| 28 | import java.security.spec.AlgorithmParameterSpec; |
| 29 | |
| 30 | /** |
| 31 | * Specifies the set of parameters required by a {@link |
| 32 | * javax.crypto.Cipher} using the Galois/Counter Mode (GCM) mode. |
| 33 | * <p> |
| 34 | * Simple block cipher modes (such as CBC) generally require only an |
| 35 | * initialization vector (such as {@code IvParameterSpec}), |
| 36 | * but GCM needs these parameters: |
| 37 | * <ul> |
| 38 | * <li>{@code IV}: Initialization Vector (IV) </li> |
| 39 | * <li>{@code tLen}: length (in bits) of authentication tag T</li> |
| 40 | * </ul> |
| 41 | * <p> |
| 42 | * In addition to the parameters described here, other GCM inputs/output |
| 43 | * (Additional Authenticated Data (AAD), Keys, block ciphers, |
| 44 | * plain/ciphertext and authentication tags) are handled in the {@code |
| 45 | * Cipher} class. |
| 46 | * <p> |
| 47 | * Please see <a href="http://www.ietf.org/rfc/rfc5116.txt"> RFC 5116 |
| 48 | * </a> for more information on the Authenticated Encryption with |
| 49 | * Associated Data (AEAD) algorithm, and <a href= |
| 50 | * "http://csrc.nist.gov/publications/nistpubs/800-38D/SP-800-38D.pdf"> |
| 51 | * NIST Special Publication 800-38D</a>, "NIST Recommendation for Block |
| 52 | * Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC." |
| 53 | * <p> |
| 54 | * The GCM specification states that {@code tLen} may only have the |
| 55 | * values {128, 120, 112, 104, 96}, or {64, 32} for certain |
| 56 | * applications. Other values can be specified for this class, but not |
| 57 | * all CSP implementations will support them. |
| 58 | * |
| 59 | * @see javax.crypto.Cipher |
| 60 | * |
| 61 | * @since 1.7 |
| 62 | */ |
| 63 | public class GCMParameterSpec implements AlgorithmParameterSpec { |
| 64 | |
| 65 | // Initialization Vector. Could use IvParameterSpec, but that |
| 66 | // would add extra copies. |
| 67 | private byte[] iv; |
| 68 | |
| 69 | // Required Tag length (in bits). |
| 70 | private int tLen; |
| 71 | |
| 72 | /** |
| 73 | * Constructs a GCMParameterSpec using the specified authentication |
| 74 | * tag bit-length and IV buffer. |
| 75 | * |
| 76 | * @param tLen the authentication tag length (in bits) |
| 77 | * @param src the IV source buffer. The contents of the buffer are |
| 78 | * copied to protect against subsequent modification. |
| 79 | * |
| 80 | * @throws IllegalArgumentException if {@code tLen} is negative, |
| 81 | * or {@code src} is null. |
| 82 | */ |
| 83 | public GCMParameterSpec(int tLen, byte[] src) { |
| 84 | if (src == null) { |
| 85 | throw new IllegalArgumentException("src array is null"); |
| 86 | } |
| 87 | |
| 88 | init(tLen, src, 0, src.length); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Constructs a GCMParameterSpec object using the specified |
| 93 | * authentication tag bit-length and a subset of the specified |
| 94 | * buffer as the IV. |
| 95 | * |
| 96 | * @param tLen the authentication tag length (in bits) |
| 97 | * @param src the IV source buffer. The contents of the |
| 98 | * buffer are copied to protect against subsequent modification. |
| 99 | * @param offset the offset in {@code src} where the IV starts |
| 100 | * @param len the number of IV bytes |
| 101 | * |
| 102 | * @throws IllegalArgumentException if {@code tLen} is negative, |
| 103 | * {@code src} is null, {@code len} or {@code offset} is negative, |
| 104 | * or the sum of {@code offset} and {@code len} is greater than the |
| 105 | * length of the {@code src} byte array. |
| 106 | */ |
| 107 | public GCMParameterSpec(int tLen, byte[] src, int offset, int len) { |
| 108 | init(tLen, src, offset, len); |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * Check input parameters. |
| 113 | */ |
| 114 | private void init(int tLen, byte[] src, int offset, int len) { |
| 115 | if (tLen < 0) { |
| 116 | throw new IllegalArgumentException( |
| 117 | "Length argument is negative"); |
| 118 | } |
| 119 | this.tLen = tLen; |
| 120 | |
| 121 | // Input sanity check |
| 122 | if ((src == null) ||(len < 0) || (offset < 0) |
| 123 | || ((len + offset) > src.length)) { |
| 124 | throw new IllegalArgumentException("Invalid buffer arguments"); |
| 125 | } |
| 126 | |
| 127 | iv = new byte[len]; |
| 128 | System.arraycopy(src, offset, iv, 0, len); |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * Returns the authentication tag length. |
| 133 | * |
| 134 | * @return the authentication tag length (in bits) |
| 135 | */ |
| 136 | public int getTLen() { |
| 137 | return tLen; |
| 138 | } |
| 139 | |
| 140 | /** |
| 141 | * Returns the Initialization Vector (IV). |
| 142 | * |
| 143 | * @return the IV. Creates a new array each time this method |
| 144 | * is called. |
| 145 | */ |
| 146 | public byte[] getIV() { |
| 147 | return iv.clone(); |
| 148 | } |
| 149 | } |