de.bb.security
Class DES

java.lang.Object
  |
  +--de.bb.security.BlockCipher
        |
        +--de.bb.security.DES

Direct Known Subclasses:

DES2, DES3

public class DES

extends BlockCipher

Fields inherited from class de.bb.security.BlockCipher

blockSize

Constructor Summary

	DES() Creates a new DesCipher object for en- and decrypting
protected	DES(int kl) for derived classes as DES2 (2-key 3-DES) and DES3 (3-key 3-DES)

Method Summary

void	decrypt(byte[] cipherText, int cipherOff, byte[] clearText, int clearOff) Decrypt one block of bytes.
void	encrypt(byte[] clearText, int clearOff, byte[] cipherText, int cipherOff) Encrypt one block of bytes.
static void	establishParity(byte[] key) Add an odd parity to the given key.
byte[]	generateKey() Create a new DES key and ensure that it is not a weak key.
static boolean	isOdd(byte _v) isOdd
static boolean	keyIsWeak(byte[] key) Check if the given key is a weak key.
protected void	makeKeyData(byte[] key)
void	setKey(byte[] key) Set the key for encryption and decryption.
void	setKeyUnchecked(byte[] key) Set the key for encryption and decryption.

Methods inherited from class de.bb.security.BlockCipher

blockSize, decryptCBC, decryptCBCAndPadd, decryptECB, encryptCBC, encryptCBCAndPadd, encryptECB, getBufferLength

Methods inherited from class java.lang.Object

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

Constructor Detail

DES

public DES()

Creates a new DesCipher object for en- and decrypting

DES

protected DES(int kl)

for derived classes as DES2 (2-key 3-DES) and DES3 (3-key 3-DES)

Method Detail

setKeyUnchecked

public void setKeyUnchecked(byte[] key)

Set the key for encryption and decryption.

Parameters:

key - the given key, an array with 8 bytes

makeKeyData

protected void makeKeyData(byte[] key)

setKey

public void setKey(byte[] key)

Set the key for encryption and decryption.

Overrides:

setKey in class BlockCipher

Parameters:

key - the given key, an array with 8 bytes

encrypt

public void encrypt(byte[] clearText,
                    int clearOff,
                    byte[] cipherText,
                    int cipherOff)

Encrypt one block of bytes. You may use one byte array as input data and output data, to encrypt in place.

Overrides:

encrypt in class BlockCipher

Parameters:

clearText - input data which is encrypted

clearOff - offset into input data

cipherText - output data which is encrypted.

cipherOff - offset into output data

decrypt

public void decrypt(byte[] cipherText,
                    int cipherOff,
                    byte[] clearText,
                    int clearOff)

Decrypt one block of bytes. You may use one byte array as input data and output data, to decrypt in place.

Overrides:

decrypt in class BlockCipher

Parameters:

cipherText - output data which is encrypted.

cipherOff - offset into output data

clearText - input data which is encrypted

clearOff - offset into input data

keyIsWeak

public static final boolean keyIsWeak(byte[] key)

Check if the given key is a weak key.

Parameters:

key - this key is testes against the known weak keys.

Returns:

true if the key is a weak key.

establishParity

public static final void establishParity(byte[] key)

Add an odd parity to the given key.

Parameters:

key - this key is made odd.

isOdd

public static final boolean isOdd(byte _v)

isOdd

generateKey

public byte[] generateKey()

Create a new DES key and ensure that it is not a weak key.

Returns:

a new allocated byte array containing the key.