net.sf.mmm.crypto.hash

Class HashCreatorImplMultipleRounds

java.lang.Object

net.sf.mmm.crypto.algorithm.AbstractSecurityAlgorithm

net.sf.mmm.crypto.algorithm.AbstractCryptoAlgorithmWithProvider

net.sf.mmm.crypto.algorithm.CryptoAlgorithmImpl

net.sf.mmm.crypto.hash.HashCreatorImplDigest

net.sf.mmm.crypto.hash.HashCreatorImplMultipleRounds

All Implemented Interfaces:

CryptoAlgorithm, CryptoChunker, CryptoProcessor, HashCreator

public class HashCreatorImplMultipleRounds
extends HashCreatorImplDigest

This is an implementation of HashCreator that calculates hashes in multiple rounds. Therefore, the actual data is hashed once and then for the number of rounds given at construction time the initial hash is hashed again with the same hash algorithm.

Since:

1.0.0

Author:

Joerg Hohwiller (hohwille at users.sourceforge.net)

Field Summary

Fields

Modifier and Type	Field and Description
private int	iterationCount
private MessageDigest	roundDigest

Fields inherited from class net.sf.mmm.crypto.algorithm.AbstractCryptoAlgorithmWithProvider

provider

Constructor Summary

Constructors

Constructor and Description
HashCreatorImplMultipleRounds(String hashAlgorithm, SecurityProvider provider, int iterationCount) The constructor.

Method Summary

Modifier and Type	Method and Description
byte[]	hash(boolean reset)

Methods inherited from class net.sf.mmm.crypto.hash.HashCreatorImplDigest

getOrCloneMessageDigest, reset, update, wrapStream

Methods inherited from class net.sf.mmm.crypto.algorithm.CryptoAlgorithmImpl

getAlgorithm

Methods inherited from class net.sf.mmm.crypto.algorithm.AbstractCryptoAlgorithmWithProvider

getProvider

Methods inherited from class net.sf.mmm.crypto.algorithm.AbstractSecurityAlgorithm

creationFailedException, creationFailedException, creationFailedException, creationFailedException, getAlgorithm, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.mmm.crypto.hash.HashCreator

hash, hash, hash, hash, process, wrapStream

Methods inherited from interface net.sf.mmm.crypto.CryptoChunker

update, update

Methods inherited from interface net.sf.mmm.crypto.CryptoProcessor

process, process, process

Methods inherited from interface net.sf.mmm.crypto.algorithm.CryptoAlgorithm

getAlgorithm

Field Detail

roundDigest

private final MessageDigest roundDigest

iterationCount

private final int iterationCount

Constructor Detail

HashCreatorImplMultipleRounds

public HashCreatorImplMultipleRounds(String hashAlgorithm,
                                     SecurityProvider provider,
                                     int iterationCount)

The constructor.

Parameters:

hashAlgorithm - the name of the hash algorithm to use (e.g. "SHA-256").

iterationCount - AbstractGetIterationCount. Has to be greater than 1.

provider - the SecurityProvider to use.

Method Detail

hash

public byte[] hash(boolean reset)

Specified by:

hash in interface HashCreator

Overrides:

hash in class HashCreatorImplDigest

Parameters:

reset - - true if this HashCreator shall be reset after the hash calculation, false otherwise. A design problem of MessageDigest is that it automatically resets itself on hashing what prevents calculating intermediate hashes but also continue the hash calculation. This API allows to workaround this limitation.

Returns:

the calculated hash of the current data.

See Also:

MessageDigest.digest()