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oracle.security.crypto.core
Class DSARandomBitsSource

java.lang.Object
oracle.security.crypto.core.RandomBitsSource
oracle.security.crypto.core.DSARandomBitsSource

public class DSARandomBitsSource

extends RandomBitsSource

A PRNG based on the algorithm described in Appendix 3.1 of FIPS PUB 186-2 and the modifications specified in the Random Number Generation and General Purpose Number Generation sections of Change Notice 1 for FIPS PUB 186-2. Use of the optional user input XSEED value is not supported by this class. An instance of this class will automatically reseed itself once it has generated 2 million x values (80 million bytes) since the last time it was seeded. This behavior is included to defend against the attack described in the Random Number Generation section of Change Notice 1 for FIPS PUB 186-2.

Since:

3.0

See Also:

RandomBitsSource, EntropySource

Constructor Summary

DSARandomBitsSource()
Creates a new seeded DSARandomBitsSource.

DSARandomBitsSource(boolean seed)
Creates a new, optionally seeded DSARandomBitsSource.

Method Summary

void	clear() Returns the internal values used by this PRNG to their initial unseeded state.
byte	randomByte() Returns the next output byte.
byte[]	randomBytes(byte[] bytes) Fills the supplied array with the requsite number of output bytes.
void	seed(byte[] seed) Seeds this PRNG with the bytes in the given byte array.
void	seed(EntropySource es) Seed this PRNG with 20 bytes generated by the given EntropySource.

Methods inherited from class oracle.security.crypto.core.RandomBitsSource

getDefault, getRNGTest, randomBigInt, randomBigInteger, seed, setDefault

Methods inherited from class java.lang.Object

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

Constructor Detail

DSARandomBitsSource

public DSARandomBitsSource()

Creates a new seeded DSARandomBitsSource.

DSARandomBitsSource

public DSARandomBitsSource(boolean seed)

Creates a new, optionally seeded DSARandomBitsSource.

Parameters:

seed - If true, the seed(byte[]) method will be invoked by tis constructor.

Method Detail

clear

public void clear()

Returns the internal values used by this PRNG to their initial unseeded state. After calling this method, the PRNG must be re-seeded before it can be used to generate additional random values.

Specified by:

clear in class RandomBitsSource

seed

public void seed(byte[] seed)

Seeds this PRNG with the bytes in the given byte array. The byte array must be no less than 20 bytes in length and no greater than 64 bytes in length.

Specified by:

seed in class RandomBitsSource

Parameters:

seed - The seeding material.

Throws:

java.lang.IllegalArgumentException - If the the length of seed is less than 20 bytes or greater than 64 bytes.

seed

public void seed(EntropySource es)

Seed this PRNG with 20 bytes generated by the given EntropySource.

Specified by:

seed in class RandomBitsSource

Parameters:

es - The EntropySource.

See Also:

EntropySource

randomByte

public byte randomByte()

Returns the next output byte. If the PRNG is in an unseeded state, an IllegalStateException is thrown.

Specified by:

randomByte in class RandomBitsSource

Throws:

java.lang.IllegalStateException - If the PRNG is in an unseeded state.

randomBytes

public byte[] randomBytes(byte[] bytes)

Fills the supplied array with the requsite number of output bytes. (If the PRNG is in an unseeded state, an exception will be thrown.)

Overrides:

randomBytes in class RandomBitsSource

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