1 /* 2 * Copyright (c) 1998, 2009, 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 com.sun.crypto.provider; 27 28 import java.nio.ByteBuffer; 29 30 import javax.crypto.MacSpi; 31 import javax.crypto.SecretKey; 32 import java.security.*; 33 import java.security.spec.*; 34 35 /** 36 * This is an implementation of the HMAC-MD5 algorithm. 37 * 38 * @author Jan Luehe 39 */ 40 public final class HmacMD5 extends MacSpi implements Cloneable { 41 42 private HmacCore hmac; 43 private static final int MD5_BLOCK_LENGTH = 64; 44 45 /** 46 * Standard constructor, creates a new HmacMD5 instance. 47 */ 48 public HmacMD5() throws NoSuchAlgorithmException { 49 hmac = new HmacCore(MessageDigest.getInstance("MD5"), 50 MD5_BLOCK_LENGTH); 51 } 52 53 /** 54 * Returns the length of the HMAC in bytes. 55 * 56 * @return the HMAC length in bytes. 57 */ 58 protected int engineGetMacLength() { 59 return hmac.getDigestLength(); 60 } 61 62 /** 63 * Initializes the HMAC with the given secret key and algorithm parameters. 64 * 65 * @param key the secret key. 66 * @param params the algorithm parameters. 67 * 68 * @exception InvalidKeyException if the given key is inappropriate for 69 * initializing this MAC. 70 * @exception InvalidAlgorithmParameterException if the given algorithm 71 * parameters are inappropriate for this MAC. 72 */ 73 protected void engineInit(Key key, AlgorithmParameterSpec params) 74 throws InvalidKeyException, InvalidAlgorithmParameterException { 75 hmac.init(key, params); 76 } 77 78 /** 79 * Processes the given byte. 80 * 81 * @param input the input byte to be processed. 82 */ 83 protected void engineUpdate(byte input) { 84 hmac.update(input); 85 } 86 87 /** 88 * Processes the first <code>len</code> bytes in <code>input</code>, 89 * starting at <code>offset</code>. 90 * 91 * @param input the input buffer. 92 * @param offset the offset in <code>input</code> where the input starts. 93 * @param len the number of bytes to process. 94 */ 95 protected void engineUpdate(byte input[], int offset, int len) { 96 hmac.update(input, offset, len); 97 } 98 99 protected void engineUpdate(ByteBuffer input) { 100 hmac.update(input); 101 } 102 103 /** 104 * Completes the HMAC computation and resets the HMAC for further use, 105 * maintaining the secret key that the HMAC was initialized with. 106 * 107 * @return the HMAC result. 108 */ 109 protected byte[] engineDoFinal() { 110 return hmac.doFinal(); 111 } 112 113 /** 114 * Resets the HMAC for further use, maintaining the secret key that the 115 * HMAC was initialized with. 116 */ 117 protected void engineReset() { 118 hmac.reset(); 119 } 120 121 /* 122 * Clones this object. 123 */ 124 public Object clone() { 125 HmacMD5 that = null; 126 try { 127 that = (HmacMD5) super.clone(); 128 that.hmac = (HmacCore) this.hmac.clone(); 129 } catch (CloneNotSupportedException e) { 130 } 131 return that; 132 } 133 }