org.bouncycastle.crypto.macs
Class MacCFBBlockCipher

java.lang.Object
  org.bouncycastle.crypto.macs.MacCFBBlockCipher

 class MacCFBBlockCipher
extends java.lang.Object

implements a Cipher-FeedBack (CFB) mode on top of a simple cipher.

Field Summary

private int	blockSize
private byte[]	cfbOutV
private byte[]	cfbV
private BlockCipher	cipher
private byte[]	IV

Constructor Summary

MacCFBBlockCipher(BlockCipher cipher, int bitBlockSize)
Basic constructor.

Method Summary

java.lang.String	getAlgorithmName() return the algorithm name and mode.
int	getBlockSize() return the block size we are operating at.
(package private) void	getMacBlock(byte[] mac)
void	init(CipherParameters params) Initialise the cipher and, possibly, the initialisation vector (IV).
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 chaining vector back to the IV and reset the underlying cipher.

Methods inherited from class java.lang.Object

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

Field Detail

IV

private byte[] IV

cfbV

private byte[] cfbV

cfbOutV

private byte[] cfbOutV

blockSize

private int blockSize

cipher

private BlockCipher cipher

Constructor Detail

MacCFBBlockCipher

public MacCFBBlockCipher(BlockCipher cipher,
                         int bitBlockSize)

Basic constructor.

Parameters:

cipher - the block cipher to be used as the basis of the feedback mode.

blockSize - the block size in bits (note: a multiple of 8)

Method Detail

init

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

Initialise the cipher and, possibly, the initialisation vector (IV). If an IV isn't passed as part of the parameter, the IV will be all zeros. An IV which is too short is handled in FIPS compliant fashion.

Parameters:

param - the key and other data required by the cipher.

Throws:

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

getAlgorithmName

public java.lang.String getAlgorithmName()

return the algorithm name and mode.

Returns:

the name of the underlying algorithm followed by "/CFB" and the block size in bits.

getBlockSize

public int getBlockSize()

return the block size we are operating at.

Returns:

the block size we are operating at (in bytes).

processBlock

public int processBlock(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException

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

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.

Throws:

DataLengthException - if there isn't enough data in in, or space in out.

java.lang.IllegalStateException - if the cipher isn't initialised.

reset

public void reset()

reset the chaining vector back to the IV and reset the underlying cipher.

getMacBlock

void getMacBlock(byte[] mac)