Source for java.security.SecureRandomSpi

   1: /* SecureRandomSpi.java --- Secure Random Service Provider Interface
   2:    Copyright (C) 1999, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package java.security;
  39: import java.io.Serializable;
  40: 
  41: /**
  42:    SecureRandomSpi is the Service Provider Interface for SecureRandom
  43:    providers. It provides an interface for providers to the 
  44:    SecureRandom engine to write their own pseudo-random number
  45:    generator.
  46: 
  47:    @since JDK 1.2       
  48: 
  49:    @author Mark Benvenuto (ivymccough@worldnet.att.net)
  50:  */
  51: public abstract class SecureRandomSpi implements Serializable
  52: {
  53:   private static final long serialVersionUID = -2991854161009191830L;
  54: 
  55:   /**
  56:      Default Constructor for SecureRandomSpi
  57:    */
  58:   public SecureRandomSpi()
  59:   {
  60:   }
  61: 
  62:   /**
  63:      Updates the seed for SecureRandomSpi but does not reset seed. 
  64:      It does to this so repeated called never decrease randomness.
  65:    */
  66:   protected abstract void engineSetSeed(byte[] seed);
  67: 
  68:   /**
  69:      Gets a user specified number of bytes depending on the length
  70:      of the array?
  71: 
  72:      @param bytes array to fill with random bytes
  73:    */
  74:   protected abstract void engineNextBytes(byte[] bytes);
  75: 
  76:   /**
  77:      Gets a user specified number of bytes specified by the 
  78:      parameter.
  79: 
  80:      @param numBytes number of random bytes to generate
  81: 
  82:      @return an array full of random bytes
  83:    */
  84:   protected abstract byte[] engineGenerateSeed(int numBytes);
  85: }