org.bouncycastle.crypto.digests

Class SkeinDigest

java.lang.Object

org.bouncycastle.crypto.digests.SkeinDigest

All Implemented Interfaces:

Digest, ExtendedDigest, Memoable

public class SkeinDigest
extends Object
implements ExtendedDigest, Memoable

Implementation of the Skein parameterised hash 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-1024
static int	SKEIN_256 256 bit block size - Skein-256
static int	SKEIN_512 512 bit block size - Skein-512

Constructor Summary

Constructors

Constructor and Description
SkeinDigest(int stateSizeBits, int digestSizeBits) Constructs a Skein digest with an internal state size and output size.
SkeinDigest(SkeinDigest digest)

Method Summary

Modifier and Type	Method and Description
Memoable	copy() Produce a copy of this object with its configuration and in its current state.
int	doFinal(byte[] out, int outOff) close the digest, producing the final digest value.
String	getAlgorithmName() return the algorithm name
int	getByteLength() Return the size in bytes of the internal buffer the digest applies it's compression function to.
int	getDigestSize() return the size, in bytes, of the digest produced by this message digest.
void	init(SkeinParameters params) Optionally initialises the Skein digest with the provided parameters. See SkeinParameters for details on the parameterisation of the Skein hash function.
void	reset() reset the digest back to it's initial state.
void	reset(Memoable other) Restore a copied object state into this object.
void	update(byte in) update the message digest with a single byte.
void	update(byte[] in, int inOff, int len) update the message digest with a block of bytes.

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-256

See Also:

Constant Field Values

SKEIN_512

public static final int SKEIN_512

512 bit block size - Skein-512

See Also:

Constant Field Values

SKEIN_1024

public static final int SKEIN_1024

1024 bit block size - Skein-1024

See Also:

Constant Field Values

Constructor Detail

SkeinDigest

public SkeinDigest(int stateSizeBits,
                   int digestSizeBits)

Constructs a Skein digest 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/digest size to produce in bits, which must be an integral number of bytes.

SkeinDigest

public SkeinDigest(SkeinDigest digest)

Method Detail

reset

public void reset(Memoable other)

Description copied from interface: Memoable

Restore a copied object state into this object.

Implementations of this method should try to avoid or minimise memory allocation to perform the reset.

Specified by:

reset in interface Memoable

Parameters:

other - an object originally copied from an object of the same type as this instance.

copy

public Memoable copy()

Description copied from interface: Memoable

Produce a copy of this object with its configuration and in its current state.

The returned object may be used simply to store the state, or may be used as a similar object starting from the copied state.

Specified by:

copy in interface Memoable

getAlgorithmName

public String getAlgorithmName()

Description copied from interface: Digest

return the algorithm name

Specified by:

getAlgorithmName in interface Digest

Returns:

the algorithm name

getDigestSize

public int getDigestSize()

Description copied from interface: Digest

return the size, in bytes, of the digest produced by this message digest.

Specified by:

getDigestSize in interface Digest

Returns:

the size, in bytes, of the digest produced by this message digest.

getByteLength

public int getByteLength()

Description copied from interface: ExtendedDigest

Return the size in bytes of the internal buffer the digest applies it's compression function to.

Specified by:

getByteLength in interface ExtendedDigest

Returns:

byte length of the digests internal buffer.

init

public void init(SkeinParameters params)

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

Parameters:

params - the parameters to apply to this engine, or null to use no parameters.

reset

public void reset()

Description copied from interface: Digest

reset the digest back to it's initial state.

Specified by:

reset in interface Digest

update

public void update(byte in)

Description copied from interface: Digest

update the message digest with a single byte.

Specified by:

update in interface Digest

Parameters:

in - the input byte to be entered.

update

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

Description copied from interface: Digest

update the message digest with a block of bytes.

Specified by:

update in interface Digest

Parameters:

in - the byte array containing the data.

inOff - the offset into the byte array where the data starts.

len - the length of the data.

doFinal

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

Description copied from interface: Digest

close the digest, producing the final digest value. The doFinal call leaves the digest reset.

Specified by:

doFinal in interface Digest

Parameters:

out - the array the digest is to be copied into.

outOff - the offset into the out array the digest is to start at.