ccs.chaos
Class SemiSecureRandom

java.lang.Object
  java.util.Random
      ccs.chaos.SemiSecureRandom

All Implemented Interfaces:

java.io.Serializable

public class SemiSecureRandom
extends java.util.Random

A PRNG designed primarily for producing the long random bytestrings required for overwriting sensitive data. It uses the statistically strong, fast, but predictable conventional PRNG, and reseeds it frequently using the default ChaosMage. This provides a good tradeoff between security and performance (the default ChaosMage is too slow to use directly). NB. Only nextBytes is automatically reseeded in this way; the other distributions and utility methods provided by the class are not. If you need these you'll have to reseed manually. This class is not designed for such use. MT-Safe.

See Also:

Serialized Form

Constructor Summary

SemiSecureRandom()

Method Summary

int	getInterval() Get the number of bytes produced between reseeds.
void	nextBytes(byte[] bytes) Obtain random bytes.
void	reseed() Reseed the predictable (fast) generator from the unpredictable (slow) one.
void	setInterval(int interval) Sets the number of bytes produced between reseeds.

Methods inherited from class java.util.Random

next, nextBoolean, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong, setSeed

Methods inherited from class java.lang.Object

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

Constructor Detail

SemiSecureRandom

public SemiSecureRandom()

Method Detail

setInterval

public void setInterval(int interval)

Sets the number of bytes produced between reseeds.

Parameters:

interval - The number

getInterval

public int getInterval()

Get the number of bytes produced between reseeds.

reseed

public void reseed()

Reseed the predictable (fast) generator from the unpredictable (slow) one.

nextBytes

public void nextBytes(byte[] bytes)

Obtain random bytes. This is the interface you should use.

Overrides:

nextBytes in class java.util.Random

Parameters:

bytes - The byte array to fill with random numbers. NB. the whole array will be taken from the fast generator, with no reseeds in mid-array even if the array is longer than the interval.