de.flexiprovider.core.shacal2
Class Shacal2

java.lang.Object
  |
  +--javax.crypto.CipherSpi
        |
        +--de.flexiprovider.api.Cipher
              |
              +--de.flexiprovider.api.BlockCipher
                    |
                    +--de.flexiprovider.core.shacal2.Shacal2

public class Shacal2

extends BlockCipher

SHACAL-2 is 256-bit symmetric block cipher with a SHA-2 structure, jointly developed by Helena Handschuh and David Naccache. It supports keys of various lengths (between 128 and 512 bits). Encrypting and decryption of a block of data is achieved in 64 rounds.

For more information, see here.

Author:

Paul Nguentcheu

Field Summary

static java.lang.String	ALG_NAME The algorithm name.
(package private) int[]	K Constant words K0...63 These are the first thirty-two bits of the fractional parts of the cube roots of the first sixty-four primes.

Fields inherited from class de.flexiprovider.api.BlockCipher

random

Fields inherited from class de.flexiprovider.api.Cipher

DECRYPT_MODE, ENCRYPT_MODE, opMode

Constructor Summary

Shacal2()

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.
void	keySchedule(byte[] key) This method implements the Shacal2 Key schedule.
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.

K

int[] K

Constant words K_0...63 These are the first thirty-two bits of the fractional parts of the cube roots of the first sixty-four primes.

Constructor Detail

Shacal2

public Shacal2()

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 Shacal2 is always 32 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 Shacal2Key or SecretKeySpec.

Overrides:

getKeySize in class Cipher

Parameters:

key - the key object

Returns:

the key size of the given key object.

Throws:

InvalidKeyException - if the key is invalid.

keySchedule

public void keySchedule(byte[] key)

This method implements the Shacal2 Key schedule.

Parameters:

key - the byte array containing the data for the key.

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 initializing 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 given key is inappropriate for initializing this cipher.

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