Implementation of the Skein family of parameterised hash functions 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.

This implementation is the basis for SkeinDigest and SkeinMac, implementing the parameter based configuration system that allows Skein to be adapted to multiple applications.
Initialising the engine with SkeinParameters allows standard and arbitrary parameters to be applied during the Skein hash function.

Implemented:

256, 512 and 1024 bit internal states.
Full 96 bit input length.
Parameters defined in the Skein specification, and arbitrary other pre and post message parameters.
Arbitrary output size in 1 byte intervals.

Not implemented:

Sub-byte length input (bit padding).
Tree hashing.

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	SkeinEngine.Configuration
public static class	SkeinEngine.Parameter
private class	SkeinEngine.UBI The Unique Block Iteration chaining mode.
private static class	SkeinEngine.UbiTweak

Field Summary

Modifier and Type	Field and Description
pack-priv long[]	chain The current chaining/state value
private static final Hashtable<K, V>	INITIAL_STATES Precalculated UBI(CFG) states for common state/output combinations without key or other pre-message params.
private long[]	initialState The initial state value
private byte[]	key The (optional) key parameter
private final int	outputSizeBytes Size of the digest output, in bytes
private static final int	PARAM_TYPE_CONFIG The parameter type for the Skein configuration block.
private static final int	PARAM_TYPE_KEY The parameter type for the Skein key.
private static final int	PARAM_TYPE_MESSAGE The parameter type for the message.
private static final int	PARAM_TYPE_OUTPUT The parameter type for the output transformation.
private SkeinEngine.Parameter[]	postMessageParameters Parameters to apply after the message, but prior to output
private SkeinEngine.Parameter[]	preMessageParameters Parameters to apply prior to the message
private final byte[]	singleByte Buffer for single byte update method
public static final int	SKEIN_1024 1024 bit block size - Skein 1024
public static final int	SKEIN_256 256 bit block size - Skein 256
public static final int	SKEIN_512 512 bit block size - Skein 512
pack-priv final ThreefishEngine	threefish Underlying Threefish tweakable block cipher
private final SkeinEngine.UBI	ubi The current UBI operation

Access	Constructor and Description
public	SkeinEngine(int the internal state size in bits - one of `SKEIN_256`, `SKEIN_512` or `SKEIN_1024`. blockSizeBits, int the output/digest size to produce in bits, which must be an integral number of bytes. outputSizeBits) Constructs a Skein engine.
public	SkeinEngine(SkeinEngine engine) Creates a SkeinEngine as an exact copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
private void	checkInitialised()
private static SkeinEngine.Parameter[]	clone(SkeinEngine.Parameter[] data, SkeinEngine.Parameter[] existing)
public Memoable	copy() Implements org.bouncycastle.util.Memoable.copy. Produce a copy of this object with its configuration and in its current state.
private void	copyIn(SkeinEngine engine)
private void	createInitialState() Calculate the initial (pre message block) chaining state.
public int	doFinal(byte[] out, int outOff)
public int	getBlockSize()
public int	getOutputSize()
public void	init(SkeinParameters the parameters to apply to this engine, or `null` to use no parameters. params) Initialises the Skein engine with the provided parameters.
private static void	initialState(int blockSize, int outputSize, long[] state)
private void	initParams(Hashtable<K, V> parameters)
private void	output(long outputSequence, byte[] out, int outOff, int outputBytes)
public void	reset(Memoable an object originally `copied` from an object of the same type as this instance. other) Implements org.bouncycastle.util.Memoable.reset. Restore a copied object state into this object.
public void	reset() Reset the engine to the initial state (with the key and any pre-message parameters , ready to accept message input.
private static void	sort(SkeinEngine.Parameter[] params)
private void	ubiComplete(int type, byte[] value)
private void	ubiFinal()
private void	ubiInit(int type)
public void	update(byte in)
public void	update(byte[] in, int inOff, int len)
private static Integer	variantIdentifier(int blockSizeBytes, int outputSizeBytes)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

chain	back to summary
pack-priv long[] chain The current chaining/state value

INITIAL_STATES	back to summary
private static final Hashtable<K, V> INITIAL_STATES Precalculated UBI(CFG) states for common state/output combinations without key or other pre-message params.

initialState	back to summary
private long[] initialState The initial state value

key	back to summary
private byte[] key The (optional) key parameter

outputSizeBytes	back to summary
private final int outputSizeBytes Size of the digest output, in bytes

PARAM_TYPE_CONFIG	back to summary
private static final int PARAM_TYPE_CONFIG The parameter type for the Skein configuration block.

PARAM_TYPE_KEY	back to summary
private static final int PARAM_TYPE_KEY The parameter type for the Skein key.

PARAM_TYPE_MESSAGE	back to summary
private static final int PARAM_TYPE_MESSAGE The parameter type for the message.

PARAM_TYPE_OUTPUT	back to summary
private static final int PARAM_TYPE_OUTPUT The parameter type for the output transformation.

postMessageParameters	back to summary
private SkeinEngine.Parameter[] postMessageParameters Parameters to apply after the message, but prior to output

preMessageParameters	back to summary
private SkeinEngine.Parameter[] preMessageParameters Parameters to apply prior to the message

singleByte	back to summary
private final byte[] singleByte Buffer for single byte update method

SKEIN_1024	back to summary
public static final int SKEIN_1024 1024 bit block size - Skein 1024

SKEIN_256	back to summary
public static final int SKEIN_256 256 bit block size - Skein 256

SKEIN_512	back to summary
public static final int SKEIN_512 512 bit block size - Skein 512

threefish	back to summary
pack-priv final ThreefishEngine threefish Underlying Threefish tweakable block cipher

ubi	back to summary
private final SkeinEngine.UBI ubi The current UBI operation

Constructor Detail

SkeinEngine back to summary

SkeinEngine	back to summary
public SkeinEngine(int blockSizeBits, int outputSizeBits) Constructs a Skein engine. Parameters blockSizeBits:int the internal state size in bits - one of `SKEIN_256`, `SKEIN_512` or `SKEIN_1024`. outputSizeBits:int the output/digest size to produce in bits, which must be an integral number of bytes.

public SkeinEngine(int blockSizeBits, int outputSizeBits)

Constructs a Skein engine.

Parameters

blockSizeBits:int: the internal state size in bits - one of SKEIN_256, SKEIN_512 or SKEIN_1024.
outputSizeBits:int: the output/digest size to produce in bits, which must be an integral number of bytes.

SkeinEngine	back to summary
public SkeinEngine(SkeinEngine engine) Creates a SkeinEngine as an exact copy of an existing instance.

Method Detail

checkInitialised	back to summary
private void checkInitialised()

clone	back to summary
private static SkeinEngine.Parameter[] clone(SkeinEngine.Parameter[] data, SkeinEngine.Parameter[] existing)

copy	back to summary
public Memoable copy() Implements org.bouncycastle.util.Memoable.copy. Doc from org.bouncycastle.util.Memoable.copy. 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.

copy

back to summary

public Memoable copy()

Implements org.bouncycastle.util.Memoable.copy.

Doc from org.bouncycastle.util.Memoable.copy.

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.

copyIn	back to summary
private void copyIn(SkeinEngine engine)

createInitialState	back to summary
private void createInitialState() Calculate the initial (pre message block) chaining state.

doFinal	back to summary
public int doFinal(byte[] out, int outOff)

getBlockSize	back to summary
public int getBlockSize()

getOutputSize	back to summary
public int getOutputSize()

init back to summary

init	back to summary
public void init(SkeinParameters params) Initialises the Skein engine with the provided parameters. See `SkeinParameters` for details on the parameterisation of the Skein hash function. Parameters params:SkeinParameters the parameters to apply to this engine, or `null` to use no parameters.

public void init(SkeinParameters params)

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

Parameters

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

initialState	back to summary
private static void initialState(int blockSize, int outputSize, long[] state)

initParams	back to summary
private void initParams(Hashtable<K, V> parameters)

output	back to summary
private void output(long outputSequence, byte[] out, int outOff, int outputBytes)

reset back to summary

reset	back to summary
public void reset(Memoable other) Implements org.bouncycastle.util.Memoable.reset. Doc from org.bouncycastle.util.Memoable.reset. Restore a copied object state into this object. Implementations of this method should try to avoid or minimise memory allocation to perform the reset. Parameters other:Memoable an object originally `copied` from an object of the same type as this instance.

public void reset(Memoable other)

Implements org.bouncycastle.util.Memoable.reset.

Doc from org.bouncycastle.util.Memoable.reset.

Restore a copied object state into this object.

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

Parameters

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

reset	back to summary
public void reset() Reset the engine to the initial state (with the key and any pre-message parameters , ready to accept message input.

sort	back to summary
private static void sort(SkeinEngine.Parameter[] params)

ubiComplete	back to summary
private void ubiComplete(int type, byte[] value)

ubiFinal	back to summary
private void ubiFinal()

ubiInit	back to summary
private void ubiInit(int type)

update	back to summary
public void update(byte in)

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

variantIdentifier	back to summary
private static Integer variantIdentifier(int blockSizeBytes, int outputSizeBytes)

org.bouncycastle.crypto.digests back to summary

private Class SkeinEngine.Configuration

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.crypto.digests.SkeinEngine.Configuration

Field Summary

Modifier and Type	Field and Description
private byte[]	bytes

Constructor Summary

Access	Constructor and Description
public	Configuration(long outputSizeBits)

Method Summary

Modifier and Type	Method and Description
public byte[]	getBytes()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

bytes	back to summary
private byte[] bytes

Constructor Detail

Configuration	back to summary
public Configuration(long outputSizeBits)

Method Detail

getBytes	back to summary
public byte[] getBytes()

org.bouncycastle.crypto.digests back to summary

public Class SkeinEngine.Parameter

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.crypto.digests.SkeinEngine.Parameter

Field Summary

Modifier and Type	Field and Description
private int	type
private byte[]	value

Constructor Summary

Access	Constructor and Description
public	Parameter(int type, byte[] value)

Method Summary

Modifier and Type	Method and Description
public int	getType()
public byte[]	getValue()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

type	back to summary
private int type

value	back to summary
private byte[] value

Constructor Detail

Parameter	back to summary
public Parameter(int type, byte[] value)

Method Detail

getType	back to summary
public int getType()

getValue	back to summary
public byte[] getValue()

org.bouncycastle.crypto.digests back to summary

private Class SkeinEngine.UBI

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.crypto.digests.SkeinEngine.UBI

The Unique Block Iteration chaining mode.

Field Summary

Modifier and Type	Field and Description
private byte[]	currentBlock Buffer for the current block of message data
private int	currentOffset Offset into the current message block
private long[]	message Buffer for message words for feedback into encrypted block
private final SkeinEngine.UbiTweak	tweak

Constructor Summary

Access	Constructor and Description
public	UBI(int blockSize)

Method Summary

Modifier and Type	Method and Description
public void	doFinal(long[] output)
private void	processBlock(long[] output)
public void	reset(SkeinEngine.UBI ubi)
public void	reset(int type)
public void	update(byte[] value, int offset, int len, long[] output)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

currentBlock	back to summary
private byte[] currentBlock Buffer for the current block of message data

currentOffset	back to summary
private int currentOffset Offset into the current message block

message	back to summary
private long[] message Buffer for message words for feedback into encrypted block

tweak	back to summary
private final SkeinEngine.UbiTweak tweak

Constructor Detail

UBI	back to summary
public UBI(int blockSize)

Method Detail

doFinal	back to summary
public void doFinal(long[] output)

processBlock	back to summary
private void processBlock(long[] output)

reset	back to summary
public void reset(SkeinEngine.UBI ubi)

reset	back to summary
public void reset(int type)

update	back to summary
public void update(byte[] value, int offset, int len, long[] output)

org.bouncycastle.crypto.digests back to summary

private Class SkeinEngine.UbiTweak

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.crypto.digests.SkeinEngine.UbiTweak

Field Summary

Modifier and Type	Field and Description
private boolean	extendedPosition Whether 64 bit position exceeded
private static final long	LOW_RANGE Point at which position might overflow long, so switch to add with carry logic
private static final long	T1_FINAL Bit 127 = final
private static final long	T1_FIRST Bit 126 = first
private long[]	tweak UBI uses a 128 bit tweak

Constructor Summary

Access	Constructor and Description
public	UbiTweak()

Method Summary

Modifier and Type	Method and Description
public void	advancePosition(int advance) Advances the position in the tweak by the specified value.
public int	getType()
public long[]	getWords()
public boolean	isFinal()
public boolean	isFirst()
public void	reset(SkeinEngine.UbiTweak tweak)
public void	reset()
public void	setFinal(boolean last)
public void	setFirst(boolean first)
public void	setType(int type)
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

extendedPosition	back to summary
private boolean extendedPosition Whether 64 bit position exceeded

LOW_RANGE	back to summary
private static final long LOW_RANGE Point at which position might overflow long, so switch to add with carry logic

T1_FINAL	back to summary
private static final long T1_FINAL Bit 127 = final

T1_FIRST	back to summary
private static final long T1_FIRST Bit 126 = first

tweak	back to summary
private long[] tweak UBI uses a 128 bit tweak

Constructor Detail

UbiTweak	back to summary
public UbiTweak()

Method Detail

advancePosition	back to summary
public void advancePosition(int advance) Advances the position in the tweak by the specified value.

getType	back to summary
public int getType()

getWords	back to summary
public long[] getWords()

isFinal	back to summary
public boolean isFinal()

isFirst	back to summary
public boolean isFirst()

reset	back to summary
public void reset(SkeinEngine.UbiTweak tweak)

reset	back to summary
public void reset()

setFinal	back to summary
public void setFinal(boolean last)

setFirst	back to summary
public void setFirst(boolean first)

setType	back to summary
public void setType(int type)

toString back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String: a string representation of the object