001/* SecureRandomSpi.java --- Secure Random Service Provider Interface
002   Copyright (C) 1999, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.security;
039import 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 */
051public 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}