package gnu.crypto.mac;
// ----------------------------------------------------------------------------
// $Id: BaseMac.java,v 1.6 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2001, 2002, Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
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// library, you may extend this exception to your version of the
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// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import gnu.crypto.hash.IMessageDigest;
import java.util.Map;
import java.security.InvalidKeyException;
/**
* <p>A base abstract class to facilitate <i>MAC</i> (Message Authentication
* Code) implementations.</p>
*
* @version $Revision: 1.6 $
*/
public abstract class BaseMac implements IMac {
// Constants and variables
// -------------------------------------------------------------------------
/** The canonical name prefix of the <i>MAC</i>. */
protected String name;
/** Reference to the underlying hash algorithm instance. */
protected IMessageDigest underlyingHash;
/** The length of the truncated output in bytes. */
protected int truncatedSize;
/** The authentication key for this instance. */
// protected transient byte[] K;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* <p>Trivial constructor for use by concrete subclasses.</p>
*
* @param name the canonical name of this instance.
*/
protected BaseMac(String name) {
super();
this.name = name;
}
/**
* <p>Trivial constructor for use by concrete subclasses.</p>
*
* @param name the canonical name of this instance.
* @param underlyingHash the underlying message digest algorithm instance.
*/
protected BaseMac(String name, IMessageDigest underlyingHash) {
this(name);
if (underlyingHash != null) {
truncatedSize = underlyingHash.hashSize();
}
this.underlyingHash = underlyingHash;
}
// Class methods
// -------------------------------------------------------------------------
// Instance methods
// -------------------------------------------------------------------------
// gnu.crypto.mac.IMac interface implementation ----------------------------
public String name() {
return name;
}
public int macSize() {
return truncatedSize;
}
public void update(byte b) {
underlyingHash.update(b);
}
public void update(byte[] b, int offset, int len) {
underlyingHash.update(b, offset, len);
}
public void reset() {
underlyingHash.reset();
}
public Object clone() throws CloneNotSupportedException
{
return super.clone();
}
// methods to be implemented by concrete subclasses ------------------------
public abstract void init(Map attributes)
throws InvalidKeyException, IllegalStateException;
public abstract byte[] digest();
public abstract boolean selfTest();
}