org.spongycastle.crypto.macs

Class SkeinMac

java.lang.Object

org.spongycastle.crypto.macs.SkeinMac

All Implemented Interfaces:

Mac

public class SkeinMac
extends java.lang.Object
implements Mac

Implementation of the Skein parameterised MAC function in 256, 512 and 1024 bit block sizes, based on the Threefish tweakable block cipher.

This is the 1.3 version of Skein defined in the Skein hash function submission to the NIST SHA-3 competition in October 2010.

Skein was designed by Niels Ferguson - Stefan Lucks - Bruce Schneier - Doug Whiting - Mihir Bellare - Tadayoshi Kohno - Jon Callas - Jesse Walker.

See Also:

SkeinEngine, SkeinParameters

Field Summary

Fields

Modifier and Type	Field and Description
static int	SKEIN_1024 1024 bit block size - Skein MAC-1024
static int	SKEIN_256 256 bit block size - Skein MAC-256
static int	SKEIN_512 512 bit block size - Skein MAC-512

Constructor Summary

Constructors

Constructor and Description
SkeinMac(int stateSizeBits, int digestSizeBits) Constructs a Skein MAC with an internal state size and output size.
SkeinMac(SkeinMac mac)

Method Summary

Modifier and Type	Method and Description
int	doFinal(byte[] out, int outOff) Compute the final stage of the MAC writing the output to the out parameter.
java.lang.String	getAlgorithmName() Return the name of the algorithm the MAC implements.
int	getMacSize() Return the block size for this MAC (in bytes).
void	init(CipherParameters params) Initialises the Skein digest with the provided parameters. See SkeinParameters for details on the parameterisation of the Skein hash function.
void	reset() Reset the MAC.
void	update(byte in) add a single byte to the mac for processing.
void	update(byte[] in, int inOff, int len)

Methods inherited from class java.lang.Object

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

Field Detail

SKEIN_256

public static final int SKEIN_256

256 bit block size - Skein MAC-256

See Also:

Constant Field Values

SKEIN_512

public static final int SKEIN_512

512 bit block size - Skein MAC-512

See Also:

Constant Field Values

SKEIN_1024

public static final int SKEIN_1024

1024 bit block size - Skein MAC-1024

See Also:

Constant Field Values

Constructor Detail

SkeinMac

public SkeinMac(int stateSizeBits,
                int digestSizeBits)

Constructs a Skein MAC with an internal state size and output size.

Parameters:

stateSizeBits - the internal state size in bits - one of SKEIN_256, SKEIN_512 or SKEIN_1024.

digestSizeBits - the output/MAC size to produce in bits, which must be an integral number of bytes.

SkeinMac

public SkeinMac(SkeinMac mac)

Method Detail

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: Mac

Return the name of the algorithm the MAC implements.

Specified by:

getAlgorithmName in interface Mac

Returns:

the name of the algorithm the MAC implements.

init

public void init(CipherParameters params)
          throws java.lang.IllegalArgumentException

Initialises the Skein digest with the provided parameters.
See SkeinParameters for details on the parameterisation of the Skein hash function.

Specified by:

init in interface Mac

Parameters:

params - an instance of SkeinParameters or KeyParameter.

Throws:

java.lang.IllegalArgumentException - if the params argument is inappropriate.

getMacSize

public int getMacSize()

Description copied from interface: Mac

Return the block size for this MAC (in bytes).

Specified by:

getMacSize in interface Mac

Returns:

the block size for this MAC in bytes.

reset

public void reset()

Description copied from interface: Mac

Reset the MAC. At the end of resetting the MAC should be in the in the same state it was after the last init (if there was one).

Specified by:

reset in interface Mac

update

public void update(byte in)

Description copied from interface: Mac

add a single byte to the mac for processing.

Specified by:

update in interface Mac

Parameters:

in - the byte to be processed.

update

public void update(byte[] in,
                   int inOff,
                   int len)

Specified by:

update in interface Mac

Parameters:

in - the array containing the input.

inOff - the index in the array the data begins at.

len - the length of the input starting at inOff.

doFinal

public int doFinal(byte[] out,
                   int outOff)

Description copied from interface: Mac

Compute the final stage of the MAC writing the output to the out parameter.

doFinal leaves the MAC in the same state it was after the last init.

Specified by:

doFinal in interface Mac

Parameters:

out - the array the MAC is to be output to.

outOff - the offset into the out buffer the output is to start at.