iaik.security.cipher

Class TripleDESKeyGenerator

java.lang.Object

javax.crypto.KeyGeneratorSpi

iaik.security.cipher.VarLengthKeyGenerator

iaik.security.cipher.TripleDESKeyGenerator

public class TripleDESKeyGenerator
extends VarLengthKeyGenerator

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
 

Version:

File Revision 18

See Also:

KeyGenerator, KeyGeneratorSpi, SecretKey, SecretKey, DESKeyGenerator, TripleDES

Constructor Summary

Constructors

Constructor and Description
TripleDESKeyGenerator()

Method Summary

Methods

Modifier and Type	Method and Description
protected javax.crypto.SecretKey	engineGenerateKey() Generates a new key.
protected void	engineInit(int strength, java.security.SecureRandom random) Initializes this key generator for the given strength with the given random seed.

Methods inherited from class iaik.security.cipher.VarLengthKeyGenerator

engineInit, engineInit

Methods inherited from class java.lang.Object

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

Constructor Detail

TripleDESKeyGenerator

public TripleDESKeyGenerator()

Method Detail

engineInit

protected void engineInit(int strength,
              java.security.SecureRandom random)

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

Overrides:

engineInit in class VarLengthKeyGenerator

Parameters:

strength - the strength of the key to be created; if -1, the default length (192) is used

random - the random seed

Throws:

java.security.InvalidParameterException - if the supplied key strength is not -1 or 112 or 128 or 168 or 192

engineGenerateKey

protected javax.crypto.SecretKey engineGenerateKey()

Description copied from class: VarLengthKeyGenerator

Generates a new key.

Overrides:

engineGenerateKey in class VarLengthKeyGenerator

Returns:

the created key