net.sf.mmm.crypto.hash

Interface HashCreator

All Superinterfaces:

CryptoAlgorithm, CryptoChunker, CryptoProcessor

All Known Implementing Classes:

HashCreatorImplCombined, HashCreatorImplDigest, HashCreatorImplMultipleRounds

public interface HashCreator
extends CryptoChunker

This is the interface for a creator of hash values. It is similar to MessageDigest but allows additional features like hashing in multiple rounds (hashing of hashes) and gives additional abstraction as well as flexibility.

Since:

1.0.0

Author:

Joerg Hohwiller (hohwille at users.sourceforge.net)

Method Summary

Modifier and Type	Method and Description
default byte[]	hash() This method calculates the current hash in the cheapest way of the underlying implementation.
byte[]	hash(boolean reset)
default byte[]	hash(byte[] input, boolean reset)
default byte[]	hash(byte[] input, int offset, int length, boolean reset)
default Hash	hash(CryptoBinary input, boolean reset)
default byte[]	process(byte[] input, int offset, int length, boolean complete) Generic method to process and transform data.
default OutputStream	wrapStream()
OutputStream	wrapStream(OutputStream out) Creates a new OutputStream wraps the given OutputStream.

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

update, update, update

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

process, process, process, reset

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

getAlgorithm

Method Detail

wrapStream

default OutputStream wrapStream()

Returns:

a new OutputStream that automatically updates all written data.

See Also:

wrapStream(OutputStream)

wrapStream

OutputStream wrapStream(OutputStream out)

Creates a new OutputStream wraps the given OutputStream. It will automatically update all written data. After data has been written, you may call hash(boolean) to get the hash of the data. This method will not reset this hasher. Therefore any previous updated data will also influence the hash. The typical usage is to call this method once on a fresh instance of HashCreator, then write data to that stream and finally get the hash.

Parameters:

out - the OutputStream to wrap.

Returns:

a wrapped OutputStream.

See Also:

wrapStream(), DigestOutputStream

process

default byte[] process(byte[] input,
                       int offset,
                       int length,
                       boolean complete)

Description copied from interface: CryptoProcessor

Generic method to process and transform data.

CryptoProcessor	Equivalent of process(input, offset, length, complete)
HashCreator	update(input, offset, length); return hash(complete);
Cryptor	return crypt(input, offset, length, true);
SignatureSigner	update(input, offset, length); return signAfterUpdate(complete);
SignatureVerifier	throw new UnsupportedOperationException();

Specified by:

process in interface CryptoProcessor

Parameters:

input - the data to process.

offset - the index where to start reading data from input.

length - the number of bytes to read from input.

complete - - true to complete/reset this processor after processing the given input, false otherwise.

Returns:

the transformed input data.

hash

default byte[] hash(byte[] input,
                    boolean reset)

Parameters:

input - the data to hash.

reset - - see hash(boolean).

Returns:

the calculated hash of the current data.

See Also:

MessageDigest.digest(byte[], int, int)

hash

default Hash hash(CryptoBinary input,
                  boolean reset)

Parameters:

input - the data to hash.

reset - - see hash(boolean).

Returns:

the calculated Hash of the given input data.

See Also:

MessageDigest.digest(byte[], int, int)

hash

default byte[] hash(byte[] input,
                    int offset,
                    int length,
                    boolean reset)

Parameters:

input - the data to hash.

offset - the index where to start reading data from input.

length - the number of bytes to read from input.

reset - - see hash(boolean).

Returns:

the calculated hash of the current data.

See Also:

MessageDigest.digest(byte[], int, int)

hash

default byte[] hash()

This method calculates the current hash in the cheapest way of the underlying implementation. The state of this HashCreator after the call of this method is therefore unspecified. Use this method only if you do not care about the further state of this HashCreator. Otherwise use hash(boolean) instead.

Returns:

the calculated hash of the current data.

See Also:

MessageDigest.digest()

hash

byte[] hash(boolean reset)

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()