ccs.crypt
Class DuplexBlockCipher

java.lang.Object
  ccs.crypt.DuplexBlockCipher

All Implemented Interfaces:

org.bouncycastle.crypto.BlockCipher

public class DuplexBlockCipher
extends java.lang.Object
implements org.bouncycastle.crypto.BlockCipher

BouncyCastle BlockCipher engines have monolithic initialisers: you set encrypt/decrypt and the key all in one operation. However, BeeTree requires its ciphers to alternate frequently, between encrypt and decrypt; under these conditions monolithic init is a performance loss, especially for blowfish which isn't very key-agile. This class is a wrapper which maintains two engines, one set to encrypt, the other to decrypt. This allows rapid changeover, at the cost of reducing key-agility further (evey key change needs two initialisations, one each way). For BeeTree this is a good tradeoff.

Constructor Summary

DuplexBlockCipher(java.lang.Class enginec)
Constructor.

Method Summary

java.lang.String	getAlgorithmName()
int	getBlockSize()
void	init(boolean isEncrypt, org.bouncycastle.crypto.CipherParameters param) Initialise the cipher engines with a new key, or merely change direction.
int	processBlock(byte[] in, int inOff, byte[] out, int outOff)
void	reset()

Methods inherited from class java.lang.Object

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

Constructor Detail

DuplexBlockCipher

public DuplexBlockCipher(java.lang.Class enginec)

Constructor.

Parameters:

enginec - The class of the engine. Must implement BlockCipher.

Method Detail

getAlgorithmName

public java.lang.String getAlgorithmName()

Specified by:

getAlgorithmName in interface org.bouncycastle.crypto.BlockCipher

getBlockSize

public int getBlockSize()

Specified by:

getBlockSize in interface org.bouncycastle.crypto.BlockCipher

init

public void init(boolean isEncrypt,
                 org.bouncycastle.crypto.CipherParameters param)

Initialise the cipher engines with a new key, or merely change direction.

Specified by:

init in interface org.bouncycastle.crypto.BlockCipher

Parameters:

isEncrypt - Set whether we're encrypting or decrypting.

param - If not null, the engines are reinitialised using this. Set this when actually re-keying, rather than just changing direction. Typically this needs to be a KeyParameter. This cut-out also neutralises the braindeadness of the CBCBlockCipher layer, which would have you reinitialise the underlying cipher for every new IV.

processBlock

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

Specified by:

processBlock in interface org.bouncycastle.crypto.BlockCipher

reset

public void reset()

Specified by:

reset in interface org.bouncycastle.crypto.BlockCipher