package gnu.crypto.key.dh;
// ----------------------------------------------------------------------------
// $Id: GnuDHKey.java,v 1.2 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2003 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
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import gnu.crypto.Registry;
import java.math.BigInteger;
import java.security.Key;
import javax.crypto.interfaces.DHKey;
import javax.crypto.spec.DHParameterSpec;
/**
* <p>A base asbtract class for both public and private Diffie-Hellman keys. It
* encapsulates the two DH numbers: <code>p</code>, and <code>g</code>.</p>
*
* <p>According to the JDK, cryptographic <i>Keys</i> all have a <i>format</i>.
* The format used in this implementation is called <i>Raw</i>, and basically
* consists of the raw byte sequences of algorithm parameters. The exact order
* of the byte sequences and the implementation details are given in each of
* the relevant <code>getEncoded()</code> methods of each of the private and
* public keys.</p>
*
* <p>Reference:</p>
* <ol>
* <li><a href="http://www.ietf.org/rfc/rfc2631.txt">Diffie-Hellman Key
* Agreement Method</a><br>
* Eric Rescorla.</li>
* </ol>
*
* @version $Revision: 1.2 $
*/
public abstract class GnuDHKey implements Key, DHKey {
// Constants and variables
// -------------------------------------------------------------------------
/** The public prime q. A prime divisor of p-1. */
protected BigInteger q;
/** The public prime p. */
protected BigInteger p;
/** The generator g. */
protected BigInteger g;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* <p>Trivial protected constructor.</p>
*
* @param q a prime divisor of p-1.
* @param p the public prime.
* @param g the generator of the group.
*/
protected GnuDHKey(BigInteger q, BigInteger p, BigInteger g) {
super();
this.q = q;
this.p = p;
this.g = g;
}
// Class methods
// -------------------------------------------------------------------------
// Instance methods
// -------------------------------------------------------------------------
// javax.crypto.interfaces.DHKey interface implementation ------------------
public DHParameterSpec getParams() {
if (q == null) {
return new DHParameterSpec(p, g);
} else {
return new DHParameterSpec(p, g, q.bitLength());
}
}
// java.security.Key interface implementation ------------------------------
public String getAlgorithm() {
return Registry.DH_KPG;
}
public String getFormat() {
return null;
}
// Other instance methods --------------------------------------------------
public BigInteger getQ() {
return q;
}
/**
* <p>Returns <code>true</code> if the designated object is an instance of
* {@link DHKey} and has the same Diffie-Hellman parameter values as this
* one.</p>
*
* @param obj the other non-null DH key to compare to.
* @return <code>true</code> if the designated object is of the same type and
* value as this one.
*/
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (!(obj instanceof DHKey)) {
return false;
}
DHKey that = (DHKey) obj;
return p.equals(that.getParams().getP()) && g.equals(that.getParams().getG());
}
}