org.bouncycastle.crypto.prng.drbg

Class HashSP800DRBG

java.lang.Object

org.bouncycastle.crypto.prng.drbg.HashSP800DRBG

All Implemented Interfaces:

SP80090DRBG

public class HashSP800DRBG
extends java.lang.Object
implements SP80090DRBG

A SP800-90A Hash DRBG.

Constructor Summary

Constructors

Constructor and Description
HashSP800DRBG(Digest digest, int securityStrength, EntropySource entropySource, byte[] personalizationString, byte[] nonce) Construct a SP800-90A Hash DRBG.

Method Summary

Modifier and Type	Method and Description
int	generate(byte[] output, byte[] additionalInput, boolean predictionResistant) Populate a passed in array with random data.
int	getBlockSize() Return the block size (in bits) of the DRBG.
void	reseed(byte[] additionalInput) Reseed the DRBG.

Methods inherited from class java.lang.Object

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

Constructor Detail

HashSP800DRBG

public HashSP800DRBG(Digest digest,
                     int securityStrength,
                     EntropySource entropySource,
                     byte[] personalizationString,
                     byte[] nonce)

Construct a SP800-90A Hash DRBG.

Minimum entropy requirement is the security strength requested.

Parameters:

digest - source digest to use for DRB stream.

securityStrength - security strength required (in bits)

entropySource - source of entropy to use for seeding/reseeding.

personalizationString - personalization string to distinguish this DRBG (may be null).

nonce - nonce to further distinguish this DRBG. SP 800-90A Rev. 1 sec. 8.6.7 requires either a value with at least (securityStrength / 2) bits of entropy, or a value expected to repeat no more often than a (securityStrength / 2)-bit random string would. The nonce may be null if the entropy source supplies the nonce's entropy along with the entropy input, that is, at least (3 * securityStrength / 2) bits on each request (SP 800-90A Rev. 1 sec. 8.6.7 and 9.1). A null nonce with an entropy source supplying less is still accepted, but the DRBG is then not compliant; this is not checked.

Method Detail

getBlockSize

public int getBlockSize()

Return the block size (in bits) of the DRBG.

Specified by:

getBlockSize in interface SP80090DRBG

Returns:

the number of bits produced on each internal round of the DRBG.

generate

public int generate(byte[] output,
                    byte[] additionalInput,
                    boolean predictionResistant)

Populate a passed in array with random data.

Specified by:

generate in interface SP80090DRBG

Parameters:

output - output array for generated bits.

additionalInput - additional input to be added to the DRBG in this step.

predictionResistant - true if a reseed should be forced, false otherwise.

Returns:

number of bits generated, -1 if a reseed required.

reseed

public void reseed(byte[] additionalInput)

Reseed the DRBG.

Specified by:

reseed in interface SP80090DRBG

Parameters:

additionalInput - additional input to be added to the DRBG in this step.