Package com.icodici.crypto.digest

Class HMAC

java.lang.Object

com.icodici.crypto.digest.Digest

com.icodici.crypto.digest.HMAC

public class HMAC
extends Digest

keyed-hash message authentication code (HMAC) implementation, according to RFC2104.

Please do not use it with MD5 and SHA1. Good ones are SHA256+. With SHA3 it also could be used though SHA3 does not require this type of algorythm as is considered to be prone to the length extension attack.

See Also:

RFC2104: HMAC

Created by sergeych on 19.12.16.

Constructor Summary

Constructors

Constructor	Description
HMAC(byte[] key)	Default implementation uses SHA256 and it's blick size.
HMAC(byte[] key, java.lang.Class<? extends Digest> hashClass)	Create new HMAC hash.

Method Summary

Modifier and Type	Method	Description
protected byte[]	_digest()	Override it to calculate and return digest of all processed data.
protected void	_update(byte[] data, int offset, int size)	Override to process sequence of bytes.
int	getLength()	Override to provide digest length in bytes.
protected Digest	hashInstance()

Methods inherited from class com.icodici.crypto.digest.Digest

base64Digest, base64Digest, base64Digest, base64Digest, digest, digest, digest, digest, getChunkSize, hexDigest, hexDigest, hexDigest, hexDigest, update, update, update, update

Methods inherited from class java.lang.Object

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

Constructor Detail

HMAC

public HMAC(byte[] key)

Default implementation uses SHA256 and it's blick size.

Parameters:

key - secret key

HMAC

public HMAC(byte[] key,
            java.lang.Class<? extends Digest> hashClass)

Create new HMAC hash.

Parameters:

key - secret key

hashClass - class of the hash to use to sign the message. SHA256+ is recommended.

Method Detail

_update

protected void _update(byte[] data,
                       int offset,
                       int size)

Description copied from class: Digest

Override to process sequence of bytes. Is called only if the #_digest() was not called. Inner logic protects from update after digest is calculated.

Specified by:

_update in class Digest

Parameters:

data - source message

offset - index to start processing from

size - number of bytes to proces

_digest

protected byte[] _digest()

Description copied from class: Digest

Override it to calculate and return digest of all processed data. It is called only once per instance.

Specified by:

_digest in class Digest

Returns:

digest

hashInstance

protected final Digest hashInstance()

getLength

public int getLength()

Description copied from class: Digest

Override to provide digest length in bytes.

Specified by:

getLength in class Digest