gnu.crypto.cipher

Class BaseCipher

java.lang.Object

gnu.crypto.cipher.BaseCipher

All Implemented Interfaces:

IBlockCipher, java.lang.Cloneable

Direct Known Subclasses:

Anubis, Blowfish, Cast5, DES, Khazad, NullCipher, RC2, Rijndael, Serpent, Square, TripleDES, Twofish

public abstract class BaseCipher
extends java.lang.Object
implements IBlockCipher

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

Version:

$Revision: 1.1 $

Field Summary

Fields

Modifier and Type	Field and Description
protected int	currentBlockSize The current block size, in bytes.
protected java.lang.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 java.lang.Object	lock The instance lock.
protected java.lang.String	name The canonical name prefix of the cipher.

Fields inherited from interface gnu.crypto.cipher.IBlockCipher

CIPHER_BLOCK_SIZE, KEY_MATERIAL

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BaseCipher(java.lang.String name, int defaultBlockSize, int defaultKeySize) Trivial constructor for use by concrete subclasses.

Method Summary

Modifier and Type	Method and Description
java.util.Iterator	blockSizes() Returns an Iterator over the supported block sizes.
abstract java.lang.Object	clone() Returns a clone of this instance.
int	currentBlockSize() Returns the currently set block size for this instance.
void	decrypt(byte[] in, int inOffset, byte[] out, int outOffset, java.lang.Object k, int bs) Decrypts exactly one block of ciphertext.
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	encrypt(byte[] in, int inOffset, byte[] out, int outOffset, java.lang.Object k, int bs) Encrypts exactly one block of plaintext.
void	encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset) Encrypts exactly one block of plaintext.
void	init(java.util.Map attributes) Initialises the algorithm with designated attributes.
java.util.Iterator	keySizes() Returns an Iterator over the supported key sizes.
java.lang.Object	makeKey(byte[] k, int bs) Expands a user-supplied key material into a session key for a designated block size.
java.lang.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

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

Methods inherited from interface gnu.crypto.cipher.IBlockCipher

blockSizes, keySizes

Field Detail

name

protected java.lang.String name

The canonical name prefix of the cipher.

defaultBlockSize

protected int defaultBlockSize

The default block size, in bytes.

defaultKeySize

protected int defaultKeySize

The default key size, in bytes.

currentBlockSize

protected int currentBlockSize

The current block size, in bytes.

currentKey

protected transient java.lang.Object currentKey

The session key for this instance.

lock

protected java.lang.Object lock

The instance lock.

Constructor Detail

BaseCipher

protected BaseCipher(java.lang.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 Detail

clone

public abstract java.lang.Object clone()

Description copied from interface: IBlockCipher

Returns a clone of this instance.

Specified by:

clone in interface IBlockCipher

Overrides:

clone in class java.lang.Object

Returns:

a clone copy of this instance.

name

public java.lang.String name()

Description copied from interface: IBlockCipher

Returns the canonical name of this instance.

Specified by:

name in interface IBlockCipher

Returns:

the canonical name of this instance.

defaultBlockSize

public int defaultBlockSize()

Description copied from interface: IBlockCipher

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()

Description copied from interface: IBlockCipher

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.

init

public void init(java.util.Map attributes)
          throws java.security.InvalidKeyException

Description copied from interface: IBlockCipher

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:

java.security.InvalidKeyException - if the key data is invalid.

See Also:

IBlockCipher.KEY_MATERIAL, IBlockCipher.CIPHER_BLOCK_SIZE

currentBlockSize

public int currentBlockSize()

Description copied from interface: IBlockCipher

Returns the currently set block size for this instance.

Specified by:

currentBlockSize in interface IBlockCipher

Returns:

the current block size for this instance.

reset

public void reset()

Description copied from interface: IBlockCipher

Resets the algorithm instance for re-initialisation and use with other characteristics. This method always succeeds.

Specified by:

reset in interface IBlockCipher

encryptBlock

public void encryptBlock(byte[] in,
                         int inOffset,
                         byte[] out,
                         int outOffset)
                  throws java.lang.IllegalStateException

Description copied from interface: IBlockCipher

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:

java.lang.IllegalStateException - if the instance is not initialised.

decryptBlock

public void decryptBlock(byte[] in,
                         int inOffset,
                         byte[] out,
                         int outOffset)
                  throws java.lang.IllegalStateException

Description copied from interface: IBlockCipher

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:

java.lang.IllegalStateException - if the instance is not initialised.

selfTest

public boolean selfTest()

Description copied from interface: IBlockCipher

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

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)

blockSizes

public java.util.Iterator blockSizes()

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

Returns:

an Iterator over the supported block sizes.

keySizes

public java.util.Iterator keySizes()

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

Returns:

an Iterator over the supported key sizes.

makeKey

public java.lang.Object makeKey(byte[] k,
                                int bs)
                         throws java.security.InvalidKeyException

Expands a user-supplied key material into a session key for a designated block size.

Parameters:

k - the user-supplied key material.

bs - the desired block size in bytes.

Returns:

an Object encapsulating the session key.

Throws:

java.lang.IllegalArgumentException - if the block size is invalid.

java.security.InvalidKeyException - if the key data is invalid.

encrypt

public void encrypt(byte[] in,
                    int inOffset,
                    byte[] out,
                    int outOffset,
                    java.lang.Object k,
                    int bs)

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 the result.

k - the session key to use.

bs - the block size to use.

Throws:

java.lang.IllegalArgumentException - if the block size is invalid.

java.lang.ArrayIndexOutOfBoundsException - if there is not enough room in either the plaintext or ciphertext buffers.

decrypt

public void decrypt(byte[] in,
                    int inOffset,
                    byte[] out,
                    int outOffset,
                    java.lang.Object k,
                    int bs)

Decrypts exactly one block of ciphertext.

Parameters:

in - the ciphertext.

inOffset - index of in from which to start considering data.

out - the plaintext.

outOffset - index of out from which to store the result.

k - the session key to use.

bs - the block size to use.

Throws:

java.lang.IllegalArgumentException - if the block size is invalid.

java.lang.ArrayIndexOutOfBoundsException - if there is not enough room in either the plaintext or ciphertext buffers.