1 /* IALG.java -- 2 Copyright (C) 2003, 2006 Free Software Foundation, Inc. 3 4 This file is a part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2 of the License, or (at 9 your option) any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; if not, write to the Free Software 18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 19 USA 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package gnu.javax.crypto.sasl.srp; 40 41 import gnu.javax.crypto.mac.IMac; 42 import gnu.javax.crypto.mac.MacFactory; 43 44 import java.security.InvalidKeyException; 45 import java.security.NoSuchAlgorithmException; 46 import java.util.HashMap; 47 48 import javax.security.sasl.SaslException; 49 50 /** 51 * A Factory class that returns IALG (Integrity Algorithm) instances that 52 * operate as described in the draft-burdis-cat-sasl-srp-04 and later. 53 */ 54 public final class IALG 55 implements Cloneable 56 { 57 private IMac hmac; 58 59 /** Private constructor to enforce instantiation through Factory method. */ IALG(final IMac hmac)60 private IALG(final IMac hmac) 61 { 62 super(); 63 64 this.hmac = hmac; 65 } 66 67 /** 68 * Returns an instance of a SASL-SRP IALG implementation. 69 * 70 * @param algorithm the name of the HMAC algorithm. 71 * @return an instance of this object. 72 */ getInstance(final String algorithm)73 static synchronized IALG getInstance(final String algorithm) 74 throws SaslException 75 { 76 final IMac hmac; 77 hmac = MacFactory.getInstance(algorithm); 78 if (hmac == null) 79 throw new SaslException("getInstance()", 80 new NoSuchAlgorithmException(algorithm)); 81 return new IALG(hmac); 82 } 83 clone()84 public Object clone() throws CloneNotSupportedException 85 { 86 return new IALG((IMac) hmac.clone()); 87 } 88 init(final KDF kdf)89 public void init(final KDF kdf) throws SaslException 90 { 91 try 92 { 93 final byte[] sk = kdf.derive(hmac.macSize()); 94 final HashMap map = new HashMap(); 95 map.put(IMac.MAC_KEY_MATERIAL, sk); 96 hmac.init(map); 97 } 98 catch (InvalidKeyException x) 99 { 100 throw new SaslException("getInstance()", x); 101 } 102 } 103 update(final byte[] data)104 public void update(final byte[] data) 105 { 106 hmac.update(data, 0, data.length); 107 } 108 update(final byte[] data, final int offset, final int length)109 public void update(final byte[] data, final int offset, final int length) 110 { 111 hmac.update(data, offset, length); 112 } 113 doFinal()114 public byte[] doFinal() 115 { 116 return hmac.digest(); 117 } 118 119 /** 120 * Returns the length (in bytes) of this SASL SRP Integrity Algorithm. 121 * 122 * @return the length, in bytes, of this integrity protection algorithm. 123 */ length()124 public int length() 125 { 126 return hmac.macSize(); 127 } 128 } 129