cryptix.provider.mode

Class PCBC

public class PCBC extends FeedbackMode

Implements a block cipher in PCBC mode. The block size is the same as that of the underlying cipher.

References:

  1. Bruce Schneier, "Section 9.10 Other Block-Cipher Modes," Applied Cryptography, 2nd edition, John Wiley & Sons, 1996

  2. sci.crypt FAQ, "Part 5: Product Ciphers," ftp://ftp.rtfm.mit.edu/pub/usenet/news.answers/cryptography-faq/part05

Copyright © 1997 Systemics Ltd on behalf of the Cryptix Development Team.
All rights reserved.

$Revision: 1.6 $

Since: Cryptix 2.2.2

Author: David Hopwood Raif S. Naffah

Constructor Summary
PCBC()
Constructs a PCBC cipher, assuming that the IV will be provided via setInitializationVector.
PCBC(Cipher cipher)
Constructs a PCBC cipher, assuming that the IV will be provided via setInitializationVector.
PCBC(Cipher cipher, byte[] iv)
Constructs a PCBC cipher, using an initialization vector provided in the constructor.
Method Summary
protected intengineBlockSize()
protected voidengineInitDecrypt(Key newkey)
protected voidengineInitEncrypt(Key newkey)
protected voidengineSetCipher(Cipher cipher)
protected intengineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
SPI: This is the main engine method for updating data.

Constructor Detail

PCBC

public PCBC()
Constructs a PCBC cipher, assuming that the IV will be provided via setInitializationVector.

The IV value should be random, but unlike CFB mode, it is not absolutely required to be unique.

PCBC

public PCBC(Cipher cipher)
Constructs a PCBC cipher, assuming that the IV will be provided via setInitializationVector. See the previous constructor for more details.

Throws: NullPointerException if cipher == null IllegalBlockSizeException if cipher.getPlaintextBlockSize() != cipher.getCiphertextBlockSize()

PCBC

public PCBC(Cipher cipher, byte[] iv)
Constructs a PCBC cipher, using an initialization vector provided in the constructor.

The IV value must be unique during the lifetime of the key. If it is not unique, at least the first block of the plaintext can be recovered.

Parameters: cipher the block cipher to use iv the initial value for the shift register (IV)

Throws: NullPointerException if cipher == null

Method Detail

engineBlockSize

protected int engineBlockSize()

engineInitDecrypt

protected void engineInitDecrypt(Key newkey)

engineInitEncrypt

protected void engineInitEncrypt(Key newkey)

engineSetCipher

protected void engineSetCipher(Cipher cipher)

engineUpdate

protected int engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
SPI: This is the main engine method for updating data. It may be called with any size of input.

in and out may be the same array, and the input and output regions may overlap.

Parameters: in the input data. inOffset the offset into in specifying where the data starts. inLen the length of the subarray. out the output array. outOffset the offset indicating where to start writing into the out array.

Returns: the number of bytes written.