iaik.security.cipher
Class TripleDESKeyGenerator

java.lang.Object
  |
  +--javax.crypto.KeyGeneratorSpi
        |
        +--iaik.security.cipher.TripleDESKeyGenerator

public class TripleDESKeyGenerator

extends KeyGeneratorSpi

This class provides the functionality of a TripleDES key generator. A key generator is used for creating secret keys for symmetric algorithms.

An application uses

 KeyGenerator key_gen = KeyGenerator.getInstance("TripleDES");
 

for creating a KeyGenerator object for the TripleDES algorithm. For actually generating the requested secret TripleDES key from the KeyGenerator object just created, an application calls the generateKey method after having initialized the generator with some random seed or relied on the default system-provided source of randomness:

 SecretKey triple_des_key = key_gen.generateKey();
 

A TripleDES key is composed of three DES keys. For extracting the inherent DES keys, an application may use the getEncoded method to get a byte array representation of the TripleDES key and subsequently split it accordingly:

  des key1 = first 8 bytes of key
  des key2 = second 8 bytes of key
  des key3 = first 8 bytes of key in case of 2 key triple DES, third 8 bytes otherwise
 

See Also:

KeyGenerator, KeyGeneratorSpi, SecretKey, SecretKey, DESKeyGenerator, TripleDES

Field Summary

protected int	key_len
protected SecureRandom	random

Constructor Summary

TripleDESKeyGenerator()

Method Summary

SecretKey	engineGenerateKey() Generates a TripleDES key from three DES keys.
void	engineInit(AlgorithmParameterSpec params, SecureRandom random) Because this TripleDES key generator needs no parameter this initialization method only throws a InvalidAlgorithmParameterException.
void	engineInit(int strength, SecureRandom random) Initializes this DES key generator for the given strength with the given random seed.
void	engineInit(SecureRandom random) Initializes this TripleDES key generator with the given random seed.

Methods inherited from class java.lang.Object

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

Field Detail

random

protected SecureRandom random

key_len

protected int key_len

Constructor Detail

TripleDESKeyGenerator

public TripleDESKeyGenerator()

Method Detail

engineInit

public void engineInit(AlgorithmParameterSpec params,
                       SecureRandom random)
                throws InvalidAlgorithmParameterException

Because this TripleDES key generator needs no parameter this initialization method only throws a InvalidAlgorithmParameterException.

Overrides:

engineInit in class KeyGeneratorSpi

Throws:

InvalidAlgorithmParameterException - since this TripleDES key generator needs no parameters

engineInit

public void engineInit(SecureRandom random)

Initializes this TripleDES key generator with the given random seed.

Overrides:

engineInit in class KeyGeneratorSpi

Parameters:

random - the random seed for this TripleDES key generator

engineInit

public void engineInit(int strength,
                       SecureRandom random)

Initializes this DES key generator for the given strength with the given random seed.

Overrides:

engineInit in class KeyGeneratorSpi

Parameters:

strength - the strength of the key to be created; 112 for TripleDES with 2 keys and 168 for TripleDES with 3 keys (default)

random - the random seed

engineGenerateKey

public SecretKey engineGenerateKey()

Generates a TripleDES key from three DES keys.

Overrides:

engineGenerateKey in class KeyGeneratorSpi

Returns:

the new created parity adjusted TripleDES key

See Also:

SecretKey