de.bb.security
Class BlockCipher

java.lang.Object
  |
  +--de.bb.security.BlockCipher

Direct Known Subclasses:

DES, RC2, RC5

public abstract class BlockCipher

extends java.lang.Object

Field Summary

protected int

blockSize

Constructor Summary

BlockCipher(int _blockSize)
Creates a new BlockCipher object.

Method Summary

int	blockSize() Query the used block size.
abstract void	decrypt(byte[] cipherText, int cipherOff, byte[] clearText, int clearOff) Decrypt one block of bytes.
void	decryptCBC(byte[] iv, byte[] cipherText, byte[] clearText) Decrypt a complete byte array wihthout padding in CBC mode.
byte[]	decryptCBCAndPadd(byte[] iv, byte[] cipherText) Decrypt a complete byte array wiht padding in CBC mode.
void	decryptECB(byte[] cipherText, byte[] clearText) Decrypt a complete byte array without padding in ECB mode.
abstract void	encrypt(byte[] clearText, int clearOff, byte[] cipherText, int cipherOff) Encrypt one block of bytes.
void	encryptCBC(byte[] iv, byte[] clearText, byte[] cipherText) Encrypt a complete byte array without padding in CBC mode.
byte[]	encryptCBCAndPadd(byte[] iv, byte[] clearText) Encrypt a complete byte array wiht padding in CBC mode.
void	encryptECB(byte[] clearText, byte[] cipherText) Encrypt a complete byte array without padding in ECB mode.
protected int	getBufferLength(int plaintextLength) Calculate the buffer length for padding
abstract void	setKey(byte[] keyData) Set a givem key.

Methods inherited from class java.lang.Object

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

Field Detail

blockSize

protected int blockSize

Constructor Detail

BlockCipher

public BlockCipher(int _blockSize)

Creates a new BlockCipher object. Derived Objects must pass its block size.

Parameters:

_blockSize - defines the size of the smalles encryptable block

Method Detail

blockSize

public final int blockSize()

Query the used block size.

Returns:

the cipers blocksize

setKey

public abstract void setKey(byte[] keyData)

Set a givem key.

Parameters:

keyData - the bytes which are used for the key

encrypt

public abstract void encrypt(byte[] clearText,
                             int clearOff,
                             byte[] cipherText,
                             int cipherOff)

Encrypt one block of bytes. You may use one byte array as input data and output data, to encrypt in place.

Parameters:

clearText - input data which is encrypted

clearOff - offset into input data

cipherText - output data which is encrypted.

cipherOff - offset into output data

decrypt

public abstract void decrypt(byte[] cipherText,
                             int cipherOff,
                             byte[] clearText,
                             int clearOff)

Decrypt one block of bytes. You may use one byte array as input data and output data, to decrypt in place.

Parameters:

cipherText - output data which is encrypted.

cipherOff - offset into output data

clearText - input data which is encrypted

clearOff - offset into input data

encryptECB

public final void encryptECB(byte[] clearText,
                             byte[] cipherText)

Encrypt a complete byte array without padding in ECB mode. The size must be a multiple of block size. You may use one byte array as input data and output data, to encrypt in place.

Parameters:

clearText - input data which is encrypted

cipherText - output data which is encrypted.

decryptECB

public final void decryptECB(byte[] cipherText,
                             byte[] clearText)

Decrypt a complete byte array without padding in ECB mode. The size must be a multiple of block size. You may use one byte array as input data and output data, to decrypt in place.

Parameters:

cipherText - output data which is encrypted.

clearText - input data which is encrypted

encryptCBC

public final void encryptCBC(byte[] iv,
                             byte[] clearText,
                             byte[] cipherText)

Encrypt a complete byte array without padding in CBC mode. The size must be a multiple of block size. You may use one byte array as input data and output data, to encrypt in place. The initialization vector is updated by this function!

Parameters:

iv - the initialization vector.

clearText - input data which is encrypted

cipherText - output data which is encrypted.

decryptCBC

public final void decryptCBC(byte[] iv,
                             byte[] cipherText,
                             byte[] clearText)

Decrypt a complete byte array wihthout padding in CBC mode. The size must be a multiple of block size. You may use one byte array as input data and output data, to decrypt in place. The initialization vector is updated by this function!

Parameters:

iv - the initialization vector.

cipherText - output data which is encrypted.

clearText - input data which is encrypted

getBufferLength

protected int getBufferLength(int plaintextLength)

Calculate the buffer length for padding

Parameters:

plaintextLength - length of input data

Returns:

plaintextLength + pad length

encryptCBCAndPadd

public final byte[] encryptCBCAndPadd(byte[] iv,
                                      byte[] clearText)

Encrypt a complete byte array wiht padding in CBC mode. The initialization vector is updated by this function!

Parameters:

iv - the initialization vector.

clearText - input data which is encrypted

Returns:

a new allocated array of bytes containing the encrypted data.

decryptCBCAndPadd

public final byte[] decryptCBCAndPadd(byte[] iv,
                                      byte[] cipherText)

Decrypt a complete byte array wiht padding in CBC mode. The initialization vector is updated by this function!

Parameters:

iv - the initialization vector.

cipherText - output data which is encrypted.

Returns:

a new allocated array of bytes containing the encrypted data.