gnu.javax.crypto.cipher

Interface IBlockCipher

All Superinterfaces:: Cloneable

Known Subinterfaces:: IAuthenticatedMode, IMode

Known Implementing Classes:: Anubis, BaseCipher, BaseMode, Blowfish, Cast5, CBC, CFB, CTR, DES, EAX, ECB, ICM, Khazad, NullCipher, OFB, Rijndael, Serpent, Square, TripleDES, Twofish

public interface IBlockCipher

extends Cloneable

The basic visible methods of any symmetric key block cipher.

A symmetric key block cipher is a function that maps n-bit plaintext blocks to n-bit ciphertext blocks; n being the cipher's block size. This encryption function is parameterised by a k-bit key, and is invertible. Its inverse is the decryption function.

Possible initialisation values for an instance of this type are:

The block size in which to operate this block cipher instance. This value is optional, if unspecified, the block cipher's default block size shall be used.
The byte array containing the user supplied key material to use for generating the cipher's session key(s). This value is mandatory and should be included in the initialisation parameters. If it isn't, an IllegalStateException will be thrown if any method, other than reset() is invoked on the instance. Furthermore, the size of this key material shall be taken as an indication on the key size in which to operate this instance.

IMPLEMENTATION NOTE: Although all the concrete classes in this package implement the Cloneable interface, it is important to note here that such an operation DOES NOT clone any session key material that may have been used in initialising the source cipher (the instance to be cloned). Instead a clone of an already initialised cipher is another instance that operates with the same block size but without any knowledge of neither key material nor key size.

Field Summary
`static String`	`CIPHER_BLOCK_SIZE` Property name of the block size in which to operate a block cipher.
`static String`	`KEY_MATERIAL` Property name of the user-supplied key material.

Method Summary
`Iterator<E>`	`blockSizes()` Returns an `Iterator` over the supported block sizes.
`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.
`Iterator<E>`	`keySizes()` Returns an `Iterator` over the supported key sizes.
`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).

CIPHER_BLOCK_SIZE

public static final String CIPHER_BLOCK_SIZE

Property name of the block size in which to operate a block cipher. The value associated with this property name is taken to be an Integer.
Field Value:
"gnu.crypto.cipher.block.size"

KEY_MATERIAL

public static final String KEY_MATERIAL

Property name of the user-supplied key material. The value associated to this property name is taken to be a byte array.
Field Value:
"gnu.crypto.cipher.key.material"

blockSizes

public Iterator<E> blockSizes()

Returns an Iterator over the supported block sizes. Each element returned by this object is an Integer.
Returns:
an Iterator over the supported block sizes.

clone

public Object clone()

Returns a clone of this instance.
Overrides:
clone in interface Object
Returns:
a clone copy of this instance.

currentBlockSize

public int currentBlockSize()
            throws IllegalStateException

Returns the currently set block size for this instance.
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.
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.
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.
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.
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,
                   IllegalStateException

Initialises the algorithm with designated attributes. Permissible names and values are described in the class documentation above.
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.
See Also:
KEY_MATERIAL, CIPHER_BLOCK_SIZE

keySizes

public Iterator<E> keySizes()

Returns an Iterator over the supported key sizes. Each element returned by this object is an Integer.
Returns:
an Iterator over the supported key sizes.

name

public String name()

Returns the canonical name of this instance.
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.

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).
Returns:
true if the implementation passes simple correctness tests. Returns false otherwise.

IBlockCipher.java -- Copyright (C) 2001, 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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