gnu.javax.crypto.cipher

Class BaseCipher

Implemented Interfaces:
Cloneable, IBlockCipher, gnu.javax.crypto.cipher.IBlockCipherSpi
Known Direct Subclasses:
Anubis, Blowfish, Cast5, DES, Khazad, NullCipher, Rijndael, Serpent, Square, TripleDES, Twofish

public abstract class BaseCipher
extends Object
implements IBlockCipher, gnu.javax.crypto.cipher.IBlockCipherSpi

A basic abstract class to facilitate implementing symmetric key block ciphers.

Field Summary

protected int
currentBlockSize
The current block size, in bytes.
protected Object
currentKey
The session key for this instance.
protected int
defaultBlockSize
The default block size, in bytes.
protected int
defaultKeySize
The default key size, in bytes.
protected Object
lock
The instance lock.
protected String
name
The canonical name prefix of the cipher.

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

CIPHER_BLOCK_SIZE, KEY_MATERIAL

Constructor Summary

BaseCipher(String name, int defaultBlockSize, int defaultKeySize)
Trivial constructor for use by concrete subclasses.

Method Summary

abstract Object
clone()
Returns a clone of this instance.
int
currentBlockSize()
Returns the currently set block size for this instance.
void
decryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)
Decrypts exactly one block of ciphertext.
int
defaultBlockSize()
Returns the default value, in bytes, of the algorithm's block size.
int
defaultKeySize()
Returns the default value, in bytes, of the algorithm's key size.
void
encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)
Encrypts exactly one block of plaintext.
void
init(Map<K,V> attributes)
Initialises the algorithm with designated attributes.
String
name()
Returns the canonical name of this instance.
void
reset()
Resets the algorithm instance for re-initialisation and use with other characteristics.
boolean
selfTest()
A correctness test that consists of basic symmetric encryption / decryption test(s) for all supported block and key sizes, as well as one (1) variable key Known Answer Test (KAT).
protected boolean
testKat(byte[] kb, byte[] ct)
protected boolean
testKat(byte[] kb, byte[] ct, byte[] pt)

Methods inherited from class java.lang.Object

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

Field Details

currentBlockSize

protected int currentBlockSize
The current block size, in bytes.

currentKey

protected Object currentKey
The session key for this instance.

defaultBlockSize

protected int defaultBlockSize
The default block size, in bytes.

defaultKeySize

protected int defaultKeySize
The default key size, in bytes.

lock

protected Object lock
The instance lock.

name

protected String name
The canonical name prefix of the cipher.

Constructor Details

BaseCipher

protected BaseCipher(String name,
                     int defaultBlockSize,
                     int defaultKeySize)
Trivial constructor for use by concrete subclasses.
Parameters:
name - the canonical name prefix of this instance.
defaultBlockSize - the default block size in bytes.
defaultKeySize - the default key size in bytes.

Method Details

clone

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

currentBlockSize

public int currentBlockSize()
Returns the currently set block size for this instance.
Specified by:
currentBlockSize in interface IBlockCipher
Returns:
the current block size for this instance.
Throws:
IllegalStateException - if the instance is not initialised.

decryptBlock

public void decryptBlock(byte[] in,
                         int inOffset,
                         byte[] out,
                         int outOffset)
            throws IllegalStateException
Decrypts exactly one block of ciphertext.
Specified by:
decryptBlock in interface IBlockCipher
Parameters:
in - the plaintext.
inOffset - index of in from which to start considering data.
out - the ciphertext.
outOffset - index of out from which to store result.
Throws:
IllegalStateException - if the instance is not initialised.

defaultBlockSize

public int defaultBlockSize()
Returns the default value, in bytes, of the algorithm's block size.
Specified by:
defaultBlockSize in interface IBlockCipher
Returns:
the default value, in bytes, of the algorithm's block size.

defaultKeySize

public int defaultKeySize()
Returns the default value, in bytes, of the algorithm's key size.
Specified by:
defaultKeySize in interface IBlockCipher
Returns:
the default value, in bytes, of the algorithm's key size.

encryptBlock

public void encryptBlock(byte[] in,
                         int inOffset,
                         byte[] out,
                         int outOffset)
            throws IllegalStateException
Encrypts exactly one block of plaintext.
Specified by:
encryptBlock in interface IBlockCipher
Parameters:
in - the plaintext.
inOffset - index of in from which to start considering data.
out - the ciphertext.
outOffset - index of out from which to store result.
Throws:
IllegalStateException - if the instance is not initialised.

init

public void init(Map<K,V> attributes)
            throws InvalidKeyException
Initialises the algorithm with designated attributes. Permissible names and values are described in the class documentation above.
Specified by:
init in interface IBlockCipher
Parameters:
attributes - a set of name-value pairs that describes the desired future behaviour of this instance.
Throws:
InvalidKeyException - if the key data is invalid.
IllegalStateException - if the instance is already initialised.

name

public String name()
Returns the canonical name of this instance.
Specified by:
name in interface IBlockCipher
Returns:
the canonical name of this instance.

reset

public void reset()
Resets the algorithm instance for re-initialisation and use with other characteristics. This method always succeeds.
Specified by:
reset in interface IBlockCipher

selfTest

public boolean selfTest()
A correctness test that consists of basic symmetric encryption / decryption test(s) for all supported block and key sizes, as well as one (1) variable key Known Answer Test (KAT).
Specified by:
selfTest in interface IBlockCipher
selfTest in interface gnu.javax.crypto.cipher.IBlockCipherSpi
Returns:
true if the implementation passes simple correctness tests. Returns false otherwise.

testKat

protected boolean testKat(byte[] kb,
                          byte[] ct)

testKat

protected boolean testKat(byte[] kb,
                          byte[] ct,
                          byte[] pt)

BaseCipher.java -- Copyright (C) 2001, 2002, 2003, 2006, 2010 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.