FortunaStandalone (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- gnu.crypto.prng.BasePRNGStandalone
- - gnu.crypto.prng.FortunaStandalone

All Implemented Interfaces:
IRandomStandalone, Serializable, Cloneable
Direct Known Subclasses:
AsyncFortunaStandalone
```
public class FortunaStandalone
extends BasePRNGStandalone
implements Serializable
```
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:
Adding Random Data
This class does not do any polling of random sources, but rather provides an interface for adding random events. Applications that use this code must provide this mechanism. We use this design because an application writer who knows the system he is targeting is in a better position to judge what random data is available.
Storing the Seed
This class implements Serializable in such a way that it writes a 64 byte seed to the stream, and reads it back again when being deserialized. This is the extent of seed file management, however, and those using this class are encouraged to think deeply about when, how often, and where to store the seed.
References:
- Niels Ferguson and Bruce Schneier, Practical Cryptography, pp. 155--184. Wiley Publishing, Indianapolis. (2003 Niels Ferguson and Bruce Schneier). ISBN 0-471-22357-3.
Modified by jrandom for I2P to use a standalone gnu-crypto SHA256, Cryptix's AES, to strip out some unnecessary dependencies and increase the buffer size. Renamed from Fortuna to FortunaStandalone so it doesn't conflict with the gnu-crypto implementation, which has been imported into GNU/classpath NOTE: As of 0.8.8, uses the java.security.MessageDigest instead of GNU Sha256Standalone
See Also:
Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected IRandomStandalone`	`generator` the underlying PRNG generator
`protected long`	`lastReseed` timestamp of last reseed
`(package private) static int`	`MIN_POOL_SIZE` minimum bytes in pool 0 before reseed
`(package private) static int`	`NUM_POOLS` number of entropy pools
`protected int`	`pool0Count` bytes added to pool 0
`protected MessageDigest[]`	`pools` null if using DevRandom
`protected int`	`reseedCount` number of reseeds performed
`static String`	`SEED` property name for the seed attribute

Fields inherited from class gnu.crypto.prng.BasePRNGStandalone
buffer, initialised, name, ndx

Constructor Summary
Constructors
Constructor and Description
FortunaStandalone()
With DevRandom disabled.
FortunaStandalone(boolean useDevRandom)

Constructors
Constructor and Description
`FortunaStandalone()` With DevRandom disabled.
`FortunaStandalone(boolean useDevRandom)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addRandomByte(byte b)` Add a random byte to the entropy pool.
`void`	`addRandomBytes(byte[] buf, int offset, int length)` Add random bytes to the entropy pool.
`Object`	`clone()` Return a copy of this object.
`void`	`fillBlock()` Unused, see AsyncFortunaStandalone
`void`	`seed(byte[] val)` Unused, see AsyncFortunaStandalone.
`void`	`setup(Map<String,byte[]> attributes)` Set up the PRNG instance.

Methods inherited from class gnu.crypto.prng.BasePRNGStandalone
addRandomBytes, init, isInitialised, name, nextByte, nextBytes, nextBytes

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

- Field Detail
  - generator
```
protected final IRandomStandalone generator
```
    the underlying PRNG generator
  - lastReseed
```
protected long lastReseed
```
    timestamp of last reseed
  - MIN_POOL_SIZE
```
static final int MIN_POOL_SIZE
```
    minimum bytes in pool 0 before reseed
    See Also:
    Constant Field Values
  - NUM_POOLS
```
static final int NUM_POOLS
```
    number of entropy pools
    See Also:
    Constant Field Values
  - pool0Count
```
protected int pool0Count
```
    bytes added to pool 0
  - pools
```
protected final MessageDigest[] pools
```
    null if using DevRandom
  - reseedCount
```
protected int reseedCount
```
    number of reseeds performed
  - SEED
```
public static final String SEED
```
    property name for the seed attribute
    See Also:
    Constant Field Values
- Constructor Detail
  - FortunaStandalone
```
public FortunaStandalone()
```
    With DevRandom disabled.
  - FortunaStandalone
```
public FortunaStandalone(boolean useDevRandom)
```
    Parameters:
    useDevRandom - if true, use DevRandom instead of the Fortuna Generator
- Method Detail
  - addRandomByte
```
public void addRandomByte(byte b)
```
    Add a random byte to the entropy pool.
    Specified by:
    addRandomByte in interface IRandomStandalone
    Overrides:
    addRandomByte in class BasePRNGStandalone
    Parameters:
    b - The byte to add.
  - addRandomBytes
```
public void addRandomBytes(byte[] buf,
                           int offset,
                           int length)
```
    Add random bytes to the entropy pool.
    Specified by:
    addRandomBytes in interface IRandomStandalone
    Overrides:
    addRandomBytes in class BasePRNGStandalone
    Parameters:
    buf - The buffer of new random bytes to add.
    offset - The offset from whence to begin reading random bytes.
    length - The number of random bytes to add.
  - clone
```
public Object clone()
```
    Return a copy of this object.
    Specified by:
    clone in interface IRandomStandalone
    Overrides:
    clone in class BasePRNGStandalone
    Returns:
    a clone copy of this instance.
  - fillBlock
```
public void fillBlock()
```
    Unused, see AsyncFortunaStandalone
    Specified by:
    fillBlock in class BasePRNGStandalone
  - seed
```
public void seed(byte[] val)
```
    Unused, see AsyncFortunaStandalone. @param val the seed data (unused)
  - setup
```
public void setup(Map<String,byte[]> attributes)
```
    Set up the PRNG instance.
    Specified by:
    setup in class BasePRNGStandalone
    Parameters:
    attributes - the attributes for setup

Class FortunaStandalone

Field Summary

Fields inherited from class gnu.crypto.prng.BasePRNGStandalone

Constructor Summary

Method Summary

Methods inherited from class gnu.crypto.prng.BasePRNGStandalone

Methods inherited from class java.lang.Object

Field Detail

generator

lastReseed

MIN_POOL_SIZE

NUM_POOLS

pool0Count

pools

reseedCount

SEED

Constructor Detail

FortunaStandalone

FortunaStandalone

Method Detail

addRandomByte

addRandomBytes

clone

fillBlock

seed

setup