FortunaRandomSource (I2P Anonymous Network - Java Documentation

java.lang.Object
- java.util.Random
- - java.security.SecureRandom
  - - net.i2p.util.RandomSource
    - - net.i2p.util.FortunaRandomSource

All Implemented Interfaces:

Serializable, EntropyHarvester
```
public class FortunaRandomSource
extends RandomSource
implements EntropyHarvester
```
Wrapper around GNU-Crypto's Fortuna PRNG. This seeds from /dev/urandom and ./prngseed.rnd on startup (if they exist), writing a new seed to ./prngseed.rnd on an explicit call to saveSeed().

See Also:

Serialized Form

Field Summary
- Fields inherited from class net.i2p.util.RandomSource
  _context

Constructor Summary

Constructors
Constructor Description

FortunaRandomSource(I2PAppContext context)
May block up to 10 seconds or forever

Constructors
Constructor	Description
`FortunaRandomSource(I2PAppContext context)`	May block up to 10 seconds or forever

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`feedEntropy(String source, byte[] data, int offset, int len)`	reseed the fortuna
`void`	`feedEntropy(String source, long data, int bitoffset, int bits)`	reseed the fortuna
`EntropyHarvester`	`harvester()`
`static void`	`main(String[] args)`	Outputs to stdout for dieharder: `java -cp build/i2p.jar net.i2p.util.FortunaRandomSource \| dieharder -a -g 200`
`protected int`	`nextBits(int numBits)`	Pull the next numBits of random data off the fortuna instance (returning 0 through 2^numBits-1 Caller must synchronize!
`boolean`	`nextBoolean()`
`byte`	`nextByte()`	Not part of java.util.SecureRandom, but added for efficiency, since Fortuna supports it.
`void`	`nextBytes(byte[] buf)`
`void`	`nextBytes(byte[] buf, int offset, int length)`	Not part of java.util.SecureRandom, but added for efficiency, since Fortuna supports it.
`double`	`nextDouble()`	Implementation from sun's java.util.Random javadocs
`float`	`nextFloat()`	Implementation from sun's java.util.Random javadocs
`double`	`nextGaussian()`	Implementation from sun's java.util.Random javadocs
`int`	`nextInt()`
`int`	`nextInt(int n)`	According to the java docs (http://java.sun.com/j2se/1.4.1/docs/api/java/util/Random.html#nextInt(int)) nextInt(n) should return a number between 0 and n (including 0 and excluding n).
`long`	`nextLong()`
`long`	`nextLong(long n)`	Like the modified nextInt, nextLong(n) returns a random number from 0 through n, including 0, excluding n.
`void`	`setSeed(byte[] buf)`
`void`	`shutdown()`	Note - methods may hang or NPE or throw IllegalStateExceptions after this

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from class java.util.Random
doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs

Methods inherited from class net.i2p.util.RandomSource
getInstance, initSeed, loadSeed, saveSeed, writeSeed

Methods inherited from class java.security.SecureRandom
generateSeed, getAlgorithm, getInstance, getInstance, getInstance, getInstance, getInstance, getInstance, getInstanceStrong, getParameters, getProvider, getSeed, next, nextBytes, reseed, reseed, setSeed, toString

- Constructor Detail
  - FortunaRandomSource
```
public FortunaRandomSource(I2PAppContext context)
```
    May block up to 10 seconds or forever
- Method Detail
  - shutdown
```
public void shutdown()
```
    Note - methods may hang or NPE or throw IllegalStateExceptions after this
    
    Since:
    
    0.8.8
  - setSeed
```
public void setSeed(byte[] buf)
```
    Overrides:
    
    setSeed in class SecureRandom
  - nextInt
```
public int nextInt(int n)
```
    According to the java docs (http://java.sun.com/j2se/1.4.1/docs/api/java/util/Random.html#nextInt(int)) nextInt(n) should return a number between 0 and n (including 0 and excluding n). However, their pseudocode, as well as sun's, kaffe's, and classpath's implementation INCLUDES NEGATIVE VALUES. Ok, so we're going to have it return between 0 and n (including 0, excluding n), since thats what it has been used for.
    
    Overrides:
    
    nextInt in class RandomSource
  - nextInt
```
public int nextInt()
```
    Overrides:
    
    nextInt in class Random
  - nextLong
```
public long nextLong(long n)
```
    Like the modified nextInt, nextLong(n) returns a random number from 0 through n, including 0, excluding n.
    
    Overrides:
    
    nextLong in class RandomSource
  - nextLong
```
public long nextLong()
```
    Overrides:
    
    nextLong in class Random
  - nextBoolean
```
public boolean nextBoolean()
```
    Overrides:
    
    nextBoolean in class Random
  - nextBytes
```
public void nextBytes(byte[] buf)
```
    Overrides:
    
    nextBytes in class SecureRandom
  - nextBytes
```
public void nextBytes(byte[] buf,
                      int offset,
                      int length)
```
    Not part of java.util.SecureRandom, but added for efficiency, since Fortuna supports it.
    
    Overrides:
    
    nextBytes in class RandomSource
    
    Since:
    
    0.8.12
  - nextByte
```
public byte nextByte()
```
    Not part of java.util.SecureRandom, but added for efficiency, since Fortuna supports it.
    
    Since:
    
    0.9.24
  - nextDouble
```
public double nextDouble()
```
    Implementation from sun's java.util.Random javadocs
    
    Overrides:
    
    nextDouble in class Random
  - nextFloat
```
public float nextFloat()
```
    Implementation from sun's java.util.Random javadocs
    
    Overrides:
    
    nextFloat in class Random
  - nextGaussian
```
public double nextGaussian()
```
    Implementation from sun's java.util.Random javadocs
    
    Overrides:
    
    nextGaussian in class Random
  - nextBits
```
protected int nextBits(int numBits)
```
    Pull the next numBits of random data off the fortuna instance (returning 0 through 2^numBits-1 Caller must synchronize!
  - harvester
```
public EntropyHarvester harvester()
```
    Overrides:
    
    harvester in class RandomSource
  - feedEntropy
```
public void feedEntropy(String source,
                        long data,
                        int bitoffset,
                        int bits)
```
    reseed the fortuna
    
    Specified by:
    
    feedEntropy in interface EntropyHarvester
    
    Overrides:
    
    feedEntropy in class RandomSource
    
    Parameters:
    
    source - origin of the entropy, allowing the harvester to determine how much to value the data
    
    bitoffset - bit index into the data array to start (using java standard big-endian)
    
    bits - how many bits to use
  - feedEntropy
```
public void feedEntropy(String source,
                        byte[] data,
                        int offset,
                        int len)
```
    reseed the fortuna
    
    Specified by:
    
    feedEntropy in interface EntropyHarvester
    
    Overrides:
    
    feedEntropy in class RandomSource
    
    Parameters:
    
    source - origin of the entropy, allowing the harvester to determine how much to value the data
    
    offset - index into the data array to start
    
    len - how many bytes to use
  - main
```
public static void main(String[] args)
```
    Outputs to stdout for dieharder: java -cp build/i2p.jar net.i2p.util.FortunaRandomSource | dieharder -a -g 200

Class FortunaRandomSource

Field Summary

Fields inherited from class net.i2p.util.RandomSource

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from class java.util.Random

Methods inherited from class net.i2p.util.RandomSource

Methods inherited from class java.security.SecureRandom

Constructor Detail

FortunaRandomSource

Method Detail

shutdown

setSeed

nextInt

nextInt

nextLong

nextLong

nextBoolean

nextBytes

nextBytes

nextByte

nextDouble

nextFloat

nextGaussian

nextBits

harvester

feedEntropy

feedEntropy

main