tribble.crypto
Class NullCipher

java.lang.Object
  tribble.crypto.AbstractCipher
      tribble.crypto.SymmetricCipher
          tribble.crypto.NullCipher

public final class NullCipher

extends SymmetricCipher

Null block cipher. Implements a symmetric block cipher that does not actually perform any encrypting or decrypting (i.e., it simply copies each input block to its output).

Since:

2005-04-25

Version:

$Revision: 1.2 $ $Date: 2005/07/06 03:09:00 $

Author:

David R. Tribble (david@tribble.com).

Copyright ©2005 by David R. Tribble, all rights reserved.
Permission is granted to freely use and distribute this source code provided that the original copyright and authorship notices remain intact.

Field Summary

Fields inherited from class tribble.crypto.SymmetricCipher

m_blockLen

Fields inherited from class tribble.crypto.AbstractCipher

m_alg, m_decrypt, m_init, m_keyLen

Constructor Summary

NullCipher()
Default constructor.

Method Summary

protected void	blockDecrypt(byte[] in, int inOff, byte[] out, int outOff) Decrypt a block of ciphertext.
protected void	blockEncrypt(byte[] in, int inOff, byte[] out, int outOff) Encrypt a block of plaintext.
protected void	clear() Reset this cipher, wiping all sensitive information.
protected void	initialize(byte[] key, boolean decrypt) Initialize this cipher.

Methods inherited from class tribble.crypto.SymmetricCipher

getBlockSize, test, test

Methods inherited from class tribble.crypto.AbstractCipher

finalize, getAlgorithm, getKeySize, getKeySizes

Methods inherited from class java.lang.Object

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

Constructor Detail

NullCipher

public NullCipher()

Default constructor.

Since:

1.1, 2005-07-05

Method Detail

initialize

protected void initialize(byte[] key,
                          boolean decrypt)
                   throws java.security.InvalidKeyException

Initialize this cipher.

Specified by:

initialize in class AbstractCipher

Parameters:

key - The symmetric (secret) key for this cipher.

decrypt - If true, this indicates that this cipher is to be initialized for decrypting, otherwise it is to be initialized for encrypting.

Throws:

java.security.InvalidKeyException

Since:

1.1, 2005-07-05

See Also:

clear()

clear

protected void clear()

Reset this cipher, wiping all sensitive information.

This method will be called after this cipher object is no longer needed. It should overwrite any sensitive data contained within this object (e.g., encryption key schedules). This cipher object can no longer be used after this method has been called.

Specified by:

clear in class AbstractCipher

Since:

1.1, 2005-07-05

See Also:

initialize()

blockEncrypt

protected void blockEncrypt(byte[] in,
                            int inOff,
                            byte[] out,
                            int outOff)

Encrypt a block of plaintext.

Specified by:

blockEncrypt in class SymmetricCipher

Parameters:

in - Array containing a single block of plaintext bytes to encrypt. The length of the block is exactly equal to the cipher block size.

inOff - Index of the first byte of the plaintext block within array in to encrypt.

out - Array that will be filled with the encrypted ciphertext block. The length of the block is exactly equal to the cipher block size.

outOff - Index of the first byte of array out to fill with the encrypted ciphertext block.

Since:

1.1, 2005-07-05

See Also:

blockDecrypt(byte[], int, byte[], int)

blockDecrypt

protected void blockDecrypt(byte[] in,
                            int inOff,
                            byte[] out,
                            int outOff)

Decrypt a block of ciphertext.

Specified by:

blockDecrypt in class SymmetricCipher

Parameters:

in - Array containing a single block of ciphertext bytes to decrypt. The length of the block is exactly equal to the cipher block size.

inOff - Index of the first byte of the ciphertext block within array in to decrypt.

out - Array that will be filled with the decrypted plaintext block. The length of the block is exactly equal to the cipher block size.

outOff - Index of the first byte of array out to fill with the decrypted plaintext block.

Since:

1.1, 2005-07-05

See Also:

blockEncrypt(byte[], int, byte[], int)