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gnu.javax.crypto.prng

Class Fortuna

Implemented Interfaces:
Cloneable, EventListener, IRandom, RandomEventListener, Serializable
public class Fortuna
extends BasePRNG
implements Serializable, RandomEventListener
The Fortuna continuously-seeded pseudo-random number generator. This generator is composed of two major pieces: the entropy accumulator and the generator function. The former takes in random bits and incorporates them into the generator's state. The latter takes this base entropy and generates pseudo-random bits from it.

There are some things users of this class must be aware of:

must
Serializable

References:

See Also:
Serialized Form

Nested Class Summary

static class
Fortuna.Generator
The Fortuna generator function.

Field Summary

static String
SEED

Fields inherited from class gnu.java.security.prng.BasePRNG

buffer, initialised, name, ndx

Constructor Summary

Fortuna()
The basic constructor.

Method Summary

void
addRandomByte(byte b)
Supplement, or possibly replace, the random state of this PRNG with a random byte.
void
addRandomBytes(byte[] buf, int offset, int length)
Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.
void
addRandomEvent(RandomEvent event)
void
fillBlock()
void
setup(Map<K,V> attributes)

Methods inherited from class gnu.java.security.prng.BasePRNG

addRandomByte, addRandomBytes, addRandomBytes, clone, fillBlock, init, isInitialised, name, nextByte, nextBytes, nextBytes, setup

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SEED

public static final String SEED
Field Value:
"gnu.crypto.prng.fortuna.seed"

Constructor Details

Fortuna

public Fortuna()
The basic constructor. Object is special, because it has no superclass, so there is no call to super().

Method Details

addRandomByte

public void addRandomByte(byte b)
Supplement, or possibly replace, the random state of this PRNG with a random byte.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Specified by:
addRandomByte in interface IRandom
Overrides:
addRandomByte in interface BasePRNG
Parameters:
b - The byte to add.

addRandomBytes

public void addRandomBytes(byte[] buf,
                           int offset,
                           int length)
Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Specified by:
addRandomBytes in interface IRandom
Overrides:
addRandomBytes in interface BasePRNG
Parameters:
offset - The offset from whence to begin reading random bytes.
length - The number of random bytes to add.
Throws:
IndexOutOfBoundsException - If offset, length, or offset+length is out of bounds.

addRandomEvent

public void addRandomEvent(RandomEvent event)
Specified by:
addRandomEvent in interface RandomEventListener

fillBlock

public void fillBlock()
            throws LimitReachedException
Overrides:
fillBlock in interface BasePRNG

setup

public void setup(Map<K,V> attributes)
Overrides:
setup in interface BasePRNG
Fortuna.java -- The Fortuna PRNG. Copyright (C) 2004, 2006 Free Software Foundation, Inc. This file is a part of GNU Classpath. GNU Classpath 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 of the License, or (at your option) any later version. GNU Classpath 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 GNU Classpath; if not, write to the Free Software Foundation, Inc., 51 Franklin St, 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.

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