Class ISAACRandom

java.lang.Object

org.apache.commons.rng.core.BaseProvider

org.apache.commons.rng.core.source32.IntProvider

org.apache.commons.rng.core.source32.ISAACRandom

All Implemented Interfaces:

RandomIntSource, RestorableUniformRandomProvider, UniformRandomProvider

public class ISAACRandom
extends IntProvider

A fast cryptographic pseudo-random number generator.

ISAAC (Indirection, Shift, Accumulate, Add, and Count) generates 32-bit random numbers. ISAAC has been designed to be cryptographically secure and is inspired by RC4. Cycles are guaranteed to be at least 2⁴⁰ values long, and they are 2⁸²⁹⁵ values long on average. The results are uniformly distributed, unbiased, and unpredictable unless you know the seed.

This code is based (with minor changes and improvements) on the original implementation of the algorithm by Bob Jenkins.

Since:

1.0

See Also:

• ISAAC: a fast cryptographic pseudo-random number generator
• ISAAC (Wikipedia)

Constructor Summary

Constructors

Constructor	Description
ISAACRandom(int[] seed)	Creates a new ISAAC random number generator.

Method Summary

Modifier and Type	Method	Description
protected byte[]	getStateInternal()	Creates a snapshot of the RNG state.
int	next()	Return the next random value.
protected void	setStateInternal(byte[] s)	Resets the RNG to the given state.

Methods inherited from class IntProvider

nextBoolean, nextBytes, nextBytes, nextDouble, nextInt, nextLong, resetCachedState

Methods inherited from class BaseProvider

checkIndex, checkStateSize, composeStateInternal, extendSeed, extendSeed, fillState, fillState, restoreState, saveState, splitStateInternal, toString

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface UniformRandomProvider

doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, nextDouble, nextDouble, nextFloat, nextFloat, nextFloat, nextInt, nextInt, nextLong, nextLong

Constructor Details

ISAACRandom

public ISAACRandom(int[] seed)

Creates a new ISAAC random number generator.

Parameters:

seed - Initial seed

Method Details

getStateInternal

protected byte[] getStateInternal()

Creates a snapshot of the RNG state.

Overrides:

getStateInternal in class IntProvider

Returns:

the internal state.

setStateInternal

protected void setStateInternal(byte[] s)

Resets the RNG to the given state.

Overrides:

setStateInternal in class IntProvider

Parameters:

s - State (previously obtained by a call to BaseProvider.getStateInternal()).

See Also:

• BaseProvider.checkStateSize(byte[],int)

next

public int next()

Return the next random value.

Returns:

the next random value.