001    /* SecureRandomSpi.java --- Secure Random Service Provider Interface
002       Copyright (C) 1999, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package java.security;
039    import java.io.Serializable;
040    
041    /**
042       SecureRandomSpi is the Service Provider Interface for SecureRandom
043       providers. It provides an interface for providers to the 
044       SecureRandom engine to write their own pseudo-random number
045       generator.
046    
047       @since JDK 1.2       
048    
049       @author Mark Benvenuto (ivymccough@worldnet.att.net)
050     */
051    public abstract class SecureRandomSpi implements Serializable
052    {
053      private static final long serialVersionUID = -2991854161009191830L;
054    
055      /**
056         Default Constructor for SecureRandomSpi
057       */
058      public SecureRandomSpi()
059      {
060      }
061    
062      /**
063         Updates the seed for SecureRandomSpi but does not reset seed. 
064         It does to this so repeated called never decrease randomness.
065       */
066      protected abstract void engineSetSeed(byte[] seed);
067    
068      /**
069         Gets a user specified number of bytes depending on the length
070         of the array?
071    
072         @param bytes array to fill with random bytes
073       */
074      protected abstract void engineNextBytes(byte[] bytes);
075    
076      /**
077         Gets a user specified number of bytes specified by the 
078         parameter.
079    
080         @param numBytes number of random bytes to generate
081    
082         @return an array full of random bytes
083       */
084      protected abstract byte[] engineGenerateSeed(int numBytes);
085    }