org.bouncycastle.crypto.engines

Class CAST5Engine

java.lang.Object

org.bouncycastle.crypto.engines.CAST5Engine

All Implemented Interfaces:

BlockCipher

Direct Known Subclasses:

CAST6Engine

public class CAST5Engine
extends java.lang.Object
implements BlockCipher

A class that provides CAST key encryption operations, such as encoding data and generating keys. All the algorithms herein are from the Internet RFC's RFC2144 - CAST5 (64bit block, 40-128bit key) RFC2612 - CAST6 (128bit block, 128-256bit key) and implement a simplified cryptography interface.

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	_Km
protected int[]	_Kr
protected static int	BLOCK_SIZE
protected static int	MAX_ROUNDS
protected static int	RED_ROUNDS

Constructor Summary

Constructors

Constructor and Description
CAST5Engine()

Method Summary

Modifier and Type	Method and Description
protected void	Bits32ToBytes(int in, byte[] b, int offset)
protected void	Bits32ToInts(int in, int[] b, int offset)
protected int	BytesTo32bits(byte[] b, int i)
protected void	CAST_Decipher(int L16, int R16, int[] result)
protected void	CAST_Encipher(int L0, int R0, int[] result) Does the 16 rounds to encrypt the block.
protected int	decryptBlock(byte[] src, int srcIndex, byte[] dst, int dstIndex) Decrypt the given input starting at the given offset and place the result in the provided buffer starting at the given offset.
protected int	encryptBlock(byte[] src, int srcIndex, byte[] dst, int dstIndex) Encrypt the given input starting at the given offset and place the result in the provided buffer starting at the given offset.
protected int	F1(int D, int Kmi, int Kri) The first of the three processing functions for the encryption and decryption.
protected int	F2(int D, int Kmi, int Kri) The second of the three processing functions for the encryption and decryption.
protected int	F3(int D, int Kmi, int Kri) The third of the three processing functions for the encryption and decryption.
java.lang.String	getAlgorithmName() Return the name of the algorithm the cipher implements.
int	getBlockSize() Return the block size for this cipher (in bytes).
void	init(boolean encrypting, CipherParameters params) initialise a CAST cipher.
protected int	IntsTo32bits(int[] b, int i)
int	processBlock(byte[] in, int inOff, byte[] out, int outOff) Process one block of input from the array in and write it to the out array.
void	reset() Reset the cipher.
protected void	setKey(byte[] key)

Methods inherited from class java.lang.Object

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

Field Detail

MAX_ROUNDS

protected static final int MAX_ROUNDS

See Also:

Constant Field Values

RED_ROUNDS

protected static final int RED_ROUNDS

See Also:

Constant Field Values

BLOCK_SIZE

protected static final int BLOCK_SIZE

See Also:

Constant Field Values

_Kr

protected int[] _Kr

_Km

protected int[] _Km

Constructor Detail

CAST5Engine

public CAST5Engine()

Method Detail

init

public void init(boolean encrypting,
                 CipherParameters params)

initialise a CAST cipher.

Specified by:

init in interface BlockCipher

Parameters:

encrypting - whether or not we are for encryption.

params - the parameters required to set up the cipher.

Throws:

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

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: BlockCipher

Return the name of the algorithm the cipher implements.

Specified by:

getAlgorithmName in interface BlockCipher

Returns:

the name of the algorithm the cipher implements.

processBlock

public int processBlock(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)

Description copied from interface: BlockCipher

Process one block of input from the array in and write it to the out array.

Specified by:

processBlock in interface BlockCipher

Parameters:

in - the array containing the input data.

inOff - offset into the in array the data starts at.

out - the array the output data will be copied into.

outOff - the offset into the out array the output will start at.

Returns:

the number of bytes processed and produced.

reset

public void reset()

Description copied from interface: BlockCipher

Reset the cipher. After resetting the cipher is in the same state as it was after the last init (if there was one).

Specified by:

reset in interface BlockCipher

getBlockSize

public int getBlockSize()

Description copied from interface: BlockCipher

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

Specified by:

getBlockSize in interface BlockCipher

Returns:

the block size for this cipher in bytes.

setKey

protected void setKey(byte[] key)

encryptBlock

protected int encryptBlock(byte[] src,
                           int srcIndex,
                           byte[] dst,
                           int dstIndex)

Encrypt the given input starting at the given offset and place the result in the provided buffer starting at the given offset.

Parameters:

src - The plaintext buffer

srcIndex - An offset into src

dst - The ciphertext buffer

dstIndex - An offset into dst

decryptBlock

protected int decryptBlock(byte[] src,
                           int srcIndex,
                           byte[] dst,
                           int dstIndex)

Decrypt the given input starting at the given offset and place the result in the provided buffer starting at the given offset.

Parameters:

src - The plaintext buffer

srcIndex - An offset into src

dst - The ciphertext buffer

dstIndex - An offset into dst

F1

protected final int F1(int D,
                       int Kmi,
                       int Kri)

The first of the three processing functions for the encryption and decryption.

Parameters:

D - the input to be processed

Kmi - the mask to be used from Km[n]

Kri - the rotation value to be used

F2

protected final int F2(int D,
                       int Kmi,
                       int Kri)

The second of the three processing functions for the encryption and decryption.

Parameters:

D - the input to be processed

Kmi - the mask to be used from Km[n]

Kri - the rotation value to be used

F3

protected final int F3(int D,
                       int Kmi,
                       int Kri)

The third of the three processing functions for the encryption and decryption.

Parameters:

D - the input to be processed

Kmi - the mask to be used from Km[n]

Kri - the rotation value to be used

CAST_Encipher

protected final void CAST_Encipher(int L0,
                                   int R0,
                                   int[] result)

Does the 16 rounds to encrypt the block.

Parameters:

L0 - the LH-32bits of the plaintext block

R0 - the RH-32bits of the plaintext block

CAST_Decipher

protected final void CAST_Decipher(int L16,
                                   int R16,
                                   int[] result)

Bits32ToInts

protected final void Bits32ToInts(int in,
                                  int[] b,
                                  int offset)

IntsTo32bits

protected final int IntsTo32bits(int[] b,
                                 int i)

Bits32ToBytes

protected final void Bits32ToBytes(int in,
                                   byte[] b,
                                   int offset)

BytesTo32bits

protected final int BytesTo32bits(byte[] b,
                                  int i)