Package gnu.crypto.prng
Class FortunaStandalone
java.lang.Object
gnu.crypto.prng.BasePRNGStandalone
gnu.crypto.prng.FortunaStandalone
- All Implemented Interfaces:
IRandomStandalone
,Serializable
,Cloneable
- Direct Known Subclasses:
AsyncFortunaStandalone
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.
- See Also:
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Nested Class Summary
Modifier and TypeClassDescriptionstatic class
The Fortuna generator function. -
Field Summary
Modifier and TypeFieldDescription(package private) final FortunaStandalone.Generator
(package private) long
(package private) static final int
(package private) static final int
(package private) int
(package private) int
(package private) final MessageDigest[]
(package private) int
static final String
Fields inherited from class gnu.crypto.prng.BasePRNGStandalone
buffer, initialised, name, ndx
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionvoid
addRandomByte
(byte b) Supplement, or possibly replace, the random state of this PRNG with a random byte.void
addRandomBytes
(byte[] buf, int offset, int length) Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.protected void
Unused, see AsyncFortunaStandalonevoid
Unused, see AsyncFortunaStandalonevoid
seed
(byte[] val) Unused, see AsyncFortunaStandalonevoid
Methods inherited from class gnu.crypto.prng.BasePRNGStandalone
addRandomBytes, clone, init, isInitialised, name, nextByte, nextBytes, nextBytes
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Field Details
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NUM_POOLS
static final int NUM_POOLS- See Also:
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MIN_POOL_SIZE
static final int MIN_POOL_SIZE- See Also:
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generator
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pools
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lastReseed
long lastReseed -
pool
int pool -
pool0Count
int pool0Count -
reseedCount
int reseedCount -
SEED
- See Also:
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Constructor Details
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FortunaStandalone
public FortunaStandalone()
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Method Details
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allocBuffer
protected void allocBuffer()Unused, see AsyncFortunaStandalone -
seed
public void seed(byte[] val) Unused, see AsyncFortunaStandalone -
setup
- Specified by:
setup
in classBasePRNGStandalone
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fillBlock
public void fillBlock()Unused, see AsyncFortunaStandalone- Specified by:
fillBlock
in classBasePRNGStandalone
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addRandomByte
public void addRandomByte(byte b) Description copied from interface:IRandomStandalone
Supplement, or possibly replace, the random state of this PRNG with a random byte.
Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an
UnsupportedOperationException
.- Specified by:
addRandomByte
in interfaceIRandomStandalone
- Overrides:
addRandomByte
in classBasePRNGStandalone
- Parameters:
b
- The byte to add.
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addRandomBytes
public void addRandomBytes(byte[] buf, int offset, int length) Description copied from interface:IRandomStandalone
Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.
Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an
UnsupportedOperationException
.- Specified by:
addRandomBytes
in interfaceIRandomStandalone
- Overrides:
addRandomBytes
in classBasePRNGStandalone
- 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.
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