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gnu.javax.crypto.mode

Class CBC

Implemented Interfaces:
Cloneable, IBlockCipher, IMode
public class CBC
extends BaseMode
implements Cloneable
The Cipher Block Chaining mode. This mode introduces feedback into the cipher by XORing the previous ciphertext block with the plaintext block before encipherment. That is, encrypting looks like this: 
  Ci = EK(Piˆ Ci-1)

Similarly, decrypting is: 

  Pi = Ci-1 ˆ DK(Ci)

Field Summary

Fields inherited from class gnu.javax.crypto.mode.BaseMode

cipher, cipherBlockSize, iv, lock, modeBlockSize, name, state

Fields inherited from interface gnu.javax.crypto.cipher.IBlockCipher

CIPHER_BLOCK_SIZE, KEY_MATERIAL

Fields inherited from interface gnu.javax.crypto.mode.IMode

DECRYPTION, ENCRYPTION, IV, MODE_BLOCK_SIZE, STATE

Method Summary

Object
clone()
Returns a clone of this instance.
void
decryptBlock(byte[] in, int i, byte[] out, int o)
Decrypts exactly one block of ciphertext.
void
encryptBlock(byte[] in, int i, byte[] out, int o)
Encrypts exactly one block of plaintext.
void
setup()
void
teardown()

Methods inherited from class gnu.javax.crypto.mode.BaseMode

blockSizes, clone, currentBlockSize, decryptBlock, defaultBlockSize, defaultKeySize, encryptBlock, init, keySizes, name, reset, selfTest, setup, teardown, update

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

clone

public Object clone()
Returns a clone of this instance.
Specified by:
clone in interface IBlockCipher
Overrides:
clone in interface BaseMode
Returns:
a clone copy of this instance.

decryptBlock

public void decryptBlock(byte[] in,
                         int i,
                         byte[] out,
                         int o)
Decrypts exactly one block of ciphertext.
Specified by:
decryptBlock in interface IBlockCipher
Overrides:
decryptBlock in interface BaseMode
Parameters:
in - the plaintext.
out - the ciphertext.
Throws:
IllegalStateException - if the instance is not initialised.

encryptBlock

public void encryptBlock(byte[] in,
                         int i,
                         byte[] out,
                         int o)
Encrypts exactly one block of plaintext.
Specified by:
encryptBlock in interface IBlockCipher
Overrides:
encryptBlock in interface BaseMode
Parameters:
in - the plaintext.
out - the ciphertext.
Throws:
IllegalStateException - if the instance is not initialised.

setup

public void setup()
Overrides:
setup in interface BaseMode

teardown

public void teardown()
Overrides:
teardown in interface BaseMode
CBC.java -- Copyright (C) 2002, 2006 Free Software Foundation, Inc. This file is a part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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