de.flexiprovider.core.shacal
Class Shacal

java.lang.Object
  |
  +--javax.crypto.CipherSpi
        |
        +--de.flexiprovider.api.Cipher
              |
              +--de.flexiprovider.api.BlockCipher
                    |
                    +--de.flexiprovider.core.shacal.Shacal

public class Shacal

extends BlockCipher

ShacalBlockCipher implements the SHACAL Cipher. It uses a block size of 160 (20 Bytes), a 128-512 bit key and uses 80 rounds for encryption/decryption.

Author:

Paul Nguentcheu

Field Summary

static java.lang.String

ALG_NAME The algorithm name.

Fields inherited from class de.flexiprovider.api.BlockCipher

random

Fields inherited from class de.flexiprovider.api.Cipher

DECRYPT_MODE, ENCRYPT_MODE, opMode

Constructor Summary

Shacal()

Method Summary

protected int	getCipherBlockSize() This method returns the blocksize, the algorithm uses.
int	getKeySize(Key key) Returns the key size of the given key object.
java.lang.String	getName()
protected void	initCipherDecrypt(SecretKey key, AlgorithmParameterSpec params) This method guarantees the AlgorithmParameterSpec compatibility.
protected void	initCipherEncrypt(SecretKey key, AlgorithmParameterSpec params) This method guarantees the AlgorithmParameterSpec compatibility.
protected void	singleBlockDecrypt(byte[] input, int inOff, byte[] output, int outOff) This method decrypts a single block of data, and may only be called, if the block cipher is in decrytion mode.
protected void	singleBlockEncrypt(byte[] input, int inOff, byte[] output, int outOff) This method encrypts a single block of data, and may only be called, if the block cipher is in encrytion mode.

Methods inherited from class de.flexiprovider.api.BlockCipher

doFinal, doFinal, engineInit, getBlockSize, getIV, getOutputSize, getParameters, initDecrypt, initDecrypt, initDecrypt, initEncrypt, initEncrypt, initEncrypt, initEncrypt, setMode, setPadding, update, update

Methods inherited from class de.flexiprovider.api.Cipher

doFinal, doFinal, engineDoFinal, engineDoFinal, engineGetBlockSize, engineGetIV, engineGetKeySize, engineGetOutputSize, engineGetParameters, engineInit, engineInit, engineSetMode, engineSetPadding, engineUpdate, engineUpdate, update

Methods inherited from class java.lang.Object

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

Field Detail

ALG_NAME

public static final java.lang.String ALG_NAME

The algorithm name.

Constructor Detail

Shacal

public Shacal()

Method Detail

getName

public java.lang.String getName()

Overrides:

getName in class Cipher

Returns:

the name of this cipher

getCipherBlockSize

protected int getCipherBlockSize()

This method returns the blocksize, the algorithm uses. This method will normaly be called by the padding scheme. It must be assured, that this method is exclusivly called, when the algorithm is either in encryption or in decryption mode. The blocksize in Shacal is always 20 bytes.

Overrides:

getCipherBlockSize in class BlockCipher

Returns:

the used blocksize

getKeySize

public int getKeySize(Key key)
               throws InvalidKeyException

Returns the key size of the given key object. Checks whether the key object is an instance of ShacalKey or SecretKeySpec.

Overrides:

getKeySize in class Cipher

Parameters:

key - the key object

Returns:

the key size of the given key object.

Throws:

InvalidKeyException - if key is invalid.

initCipherEncrypt

protected void initCipherEncrypt(SecretKey key,
                                 AlgorithmParameterSpec params)
                          throws InvalidKeyException

This method guarantees the AlgorithmParameterSpec compatibility. As these are not used here it just calls the origin InitDecrypt method.

Overrides:

initCipherEncrypt in class BlockCipher

Parameters:

key - the SecretKey which has to be used to decrypt data.

params - algorithmParameterSpec, not used for here

Throws:

InvalidKeyException - if the given key is inappropriate for initialising this cipher.

initCipherDecrypt

protected void initCipherDecrypt(SecretKey key,
                                 AlgorithmParameterSpec params)
                          throws InvalidKeyException

This method guarantees the AlgorithmParameterSpec compatibility. As these are not used here it just calls the origin InitDecrypt method.

Overrides:

initCipherDecrypt in class BlockCipher

Parameters:

key - the SecretKey which has to be used to decrypt data.

params - algorithmParameterSpec, not used for here

Throws:

InvalidKeyException - if the key is invalid.

singleBlockDecrypt

protected void singleBlockDecrypt(byte[] input,
                                  int inOff,
                                  byte[] output,
                                  int outOff)

This method decrypts a single block of data, and may only be called, if the block cipher is in decrytion mode. It has to be asured that the array in contains a whole block starting at inOffset and that out is large enough to hold an decrypted block starting at outOffset

Overrides:

singleBlockDecrypt in class BlockCipher

Parameters:

input - array of bytes which contains the ciphertext to be decrypted

inOff - index in array in, where the ciphertext block starts

output - array of bytes which will contain the plaintext starting at outOffset

outOff - index in array out, where the plaintext block will start

singleBlockEncrypt

protected void singleBlockEncrypt(byte[] input,
                                  int inOff,
                                  byte[] output,
                                  int outOff)

This method encrypts a single block of data, and may only be called, if the block cipher is in encrytion mode. It has to be asured that the array in contains a whole block starting at inOffset and that out is large enough to hold an encrypted block starting at outOffset

Overrides:

singleBlockEncrypt in class BlockCipher

Parameters:

input - array of bytes which contains the plaintext to be encrypted

inOff - index in array in, where the plaintext block starts

output - array of bytes which will contain the ciphertext startig at outOffset

outOff - index in array out, where the ciphertext block will start