org.bouncycastle.crypto.engines

Class CAST5Engine

Implemented Interfaces:
BlockCipher
Known Direct 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

protected static int
BLOCK_SIZE
protected static int
M32
protected static int
MAX_ROUNDS
protected static int
RED_ROUNDS
protected static int[]
S1
protected static int[]
S2
protected static int[]
S3
protected static int[]
S4
protected static int[]
S5
protected static int[]
S6
protected static int[]
S7
protected static int[]
S8
protected int[]
_Km
protected int[]
_Kr

Constructor Summary

CAST5Engine()

Method Summary

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, result[] )
protected void
CAST_Encipher(int L0, int R0, result[] )
Does the 16 rounds to encrypt the block.
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.
protected int
IntsTo32bits(int[] b, int i)
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.
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.
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)

Field Details

BLOCK_SIZE

protected static final int BLOCK_SIZE

Field Value:
8


M32

protected static final int M32

Field Value:
-1


MAX_ROUNDS

protected static final int MAX_ROUNDS

Field Value:
16


RED_ROUNDS

protected static final int RED_ROUNDS

Field Value:
12


S1

protected static final int[] S1


S2

protected static final int[] S2


S3

protected static final int[] S3


S4

protected static final int[] S4


S5

protected static final int[] S5


S6

protected static final int[] S6


S7

protected static final int[] S7


S8

protected static final int[] S8


_Km

protected int[] _Km


_Kr

protected int[] _Kr

Constructor Details

CAST5Engine

public CAST5Engine()

Method Details

Bits32ToBytes

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


Bits32ToInts

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


BytesTo32bits

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


CAST_Decipher

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


CAST_Encipher

protected final void CAST_Encipher(int L0,
                                   int R0,
                                   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


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


IntsTo32bits

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


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


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


getAlgorithmName

public String getAlgorithmName()
Return the name of the algorithm the cipher implements.
Specified by:
getAlgorithmName in interface BlockCipher

Returns:
the name of the algorithm the cipher implements.


getBlockSize

public int getBlockSize()
Return the block size for this cipher (in bytes).
Specified by:
getBlockSize in interface BlockCipher

Returns:
the block size for this cipher in bytes.


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.


processBlock

public 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.
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()
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


setKey

protected void setKey(byte[] key)