HashCreator (JavaDocs for mmm-all 1.0.0-SNAPSHOT)

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

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	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 io.github.mmm.crypto.algorithm.CryptoAlgorithm
getAlgorithm

Methods inherited from interface io.github.mmm.crypto.CryptoChunker
update, update, update

Methods inherited from interface io.github.mmm.crypto.CryptoProcessor
process, process, process, reset

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()