org.bouncycastle.crypto.util
Class JournalingSecureRandom

java.lang.Object
  java.util.Random
      java.security.SecureRandom
          org.bouncycastle.crypto.util.JournalingSecureRandom

All Implemented Interfaces:

java.io.Serializable

public class JournalingSecureRandom

extends java.security.SecureRandom

A SecureRandom that maintains a journal of its output. This can be used to recreate an output that was based on randomness For the transcript to be reusable, the order of the requests for randomness during recreation must be consistent with the initial requests and no other sources of randomness may be used.

See Also:

Serialized Form

Constructor Summary

JournalingSecureRandom()
Default constructor that takes an arbitrary SecureRandom as initial random

JournalingSecureRandom(byte[] transcript, java.security.SecureRandom random)
Constructor with a prior transcript.

JournalingSecureRandom(java.security.SecureRandom random)
Base constructor - no prior transcript.

Method Summary

void	clear() Clear the internals
byte[]	getFullTranscript() Return the full transcript, such as would be needed to create a copy of this JournalingSecureRandom,
byte[]	getTranscript() Return the transcript so far,
void	nextBytes(byte[] bytes) Fill bytes with random data, journaling the random data before returning or re-use previously used random data, depending on the state of the transcript.
void	reset() Resets the index to zero such that the randomness will now be reused

Methods inherited from class java.security.SecureRandom

generateSeed, getInstance, getInstance, getInstance, getProvider, getSeed, next, setSeed, setSeed

Methods inherited from class java.util.Random

nextBoolean, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong

Methods inherited from class java.lang.Object

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

Constructor Detail

JournalingSecureRandom

public JournalingSecureRandom()

Default constructor that takes an arbitrary SecureRandom as initial random

JournalingSecureRandom

public JournalingSecureRandom(java.security.SecureRandom random)

Base constructor - no prior transcript.

Parameters:

random - source of randomness we will be journaling.

JournalingSecureRandom

public JournalingSecureRandom(byte[] transcript,
                              java.security.SecureRandom random)

Constructor with a prior transcript. Both the transcript used and any new randomness are journaled.

Parameters:

transcript - initial transcript of randomness.

random - source of randomness we will be journaling when the transcript runs out.

Method Detail

nextBytes

public final void nextBytes(byte[] bytes)

Fill bytes with random data, journaling the random data before returning or re-use previously used random data, depending on the state of the transcript.

Parameters:

bytes - a block of bytes to be filled with random data.

clear

public void clear()

Clear the internals

reset

public void reset()

Resets the index to zero such that the randomness will now be reused

getTranscript

public byte[] getTranscript()

Return the transcript so far,

Returns:

a copy of the randomness produced so far.

getFullTranscript

public byte[] getFullTranscript()

Return the full transcript, such as would be needed to create a copy of this JournalingSecureRandom,

Returns:

a copy of the original transcript on construction, plus any randomness added since.