package gnu.crypto.jce.prng;
// ----------------------------------------------------------------------------
// $Id: ARCFourRandomSpi.java,v 1.3 2005/10/06 04:24:15 rsdio Exp $
//
// Copyright (C) 2002, 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 gnu.crypto.prng.ARCFour;
import gnu.crypto.prng.IRandom;
import gnu.crypto.prng.LimitReachedException;
import gnu.crypto.prng.PRNGFactory;
import java.security.SecureRandomSpi;
import java.util.HashMap;
/**
* Implementation of the <i>Service Provider Interface</i> (<b>SPI</b>)
* for the ARCFOUR keystream generator.
*
* @version $Revision: 1.3 $
*/
public class ARCFourRandomSpi extends SecureRandomSpi {
// Constants and variables
// -------------------------------------------------------------------------
/** Our underlying prng instance. */
private IRandom adaptee;
/** Have we been initialized? */
private boolean virgin;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* Default 0-arguments constructor.
*/
public ARCFourRandomSpi() {
super();
adaptee = PRNGFactory.getInstance(Registry.ARCFOUR_PRNG);
virgin = true;
}
// Class methods
// -------------------------------------------------------------------------
// Instance methods
// -------------------------------------------------------------------------
// java.security.SecureRandomSpi interface implementation ------------------
public byte[] engineGenerateSeed(int numBytes) {
if (numBytes < 1) {
return new byte[0];
}
byte[] result = new byte[numBytes];
this.engineNextBytes(result);
return result;
}
public void engineNextBytes(byte[] bytes) {
if (virgin) {
this.engineSetSeed(new byte[0]);
}
try {
adaptee.nextBytes(bytes, 0, bytes.length);
} catch (LimitReachedException ignored) {
}
}
public void engineSetSeed(byte[] seed) {
HashMap attributes = new HashMap();
attributes.put(ARCFour.ARCFOUR_KEY_MATERIAL, seed);
adaptee.init(attributes);
virgin = false;
}
}