iaik.security.cipher

Class VarLengthKeyGenerator

java.lang.Object

javax.crypto.KeyGeneratorSpi

iaik.security.cipher.VarLengthKeyGenerator

Direct Known Subclasses:

AES192KeyGenerator, AES256KeyGenerator, AESKeyGenerator, ARCFOURKeyGenerator, BlowfishKeyGenerator, Camellia192KeyGenerator, Camellia256KeyGenerator, CamelliaKeyGenerator, CAST128KeyGenerator, DESKeyGenerator, GOSTKeyGenerator, HMacGOSTKeyGenerator, HMacMd5KeyGenerator, HMacRipeMd128KeyGenerator, HMacRipeMd160KeyGenerator, HMacSha224KeyGenerator, HMacSha256KeyGenerator, HMacSha384KeyGenerator, HMacSha512KeyGenerator, HMacShaKeyGenerator, HMacWhirlpoolKeyGenerator, MARSKeyGenerator, RC2KeyGenerator, RijndaelKeyGenerator, SerpentKeyGenerator, TripleDESKeyGenerator, TwofishKeyGenerator

public abstract class VarLengthKeyGenerator
extends javax.crypto.KeyGeneratorSpi

This class provides the functionality of KeyGenerator for generating keys with variable length. It is an abstract class that is used by a number of different keygenerators.

An application uses e.g.

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

to create a KeyGenerator object for the given algorithm. For actually generating the requested secret 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 new_key = key_gen.generateKey();
 

Version:

File Revision 19

See Also:

KeyGenerator, KeyGeneratorSpi, SecretKey, SecretKey

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	VarLengthKeyGenerator(java.lang.String algorithmName, int minLength, int maxLength, int defaultLength) Creates a new KeyGanerator with given minimum, maximum, and default key length.

Method Summary

Methods

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

Constructor Detail

VarLengthKeyGenerator

protected VarLengthKeyGenerator(java.lang.String algorithmName,
                     int minLength,
                     int maxLength,
                     int defaultLength)

Creates a new KeyGanerator with given minimum, maximum, and default key length. Only internally used.

Parameters:

algorithmName - the name of the algorithm

minLength - the minimum key length

maxLength - the maximum key length

defaultLength - the default key length

Method Detail

engineInit

protected void engineInit(java.security.spec.AlgorithmParameterSpec params,
              java.security.SecureRandom random)
                   throws java.security.InvalidAlgorithmParameterException

Initializes this key generator with the given random seed. Parameters are not required. The strength defaults to the default length.

Specified by:

engineInit in class javax.crypto.KeyGeneratorSpi

Parameters:

params - not required

random - the random seed

Throws:

java.security.InvalidAlgorithmParameterException - if parameters are supplied

engineInit

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

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

Specified by:

engineInit in class javax.crypto.KeyGeneratorSpi

Parameters:

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

random - the random seed

Throws:

java.security.InvalidParameterException - if the supplied key strength is shorter than the minimum required length or longer than the maximum required length

engineInit

protected void engineInit(java.security.SecureRandom random)

Initializes this key generator with the given random seed. The strength defaults to the default length.

Specified by:

engineInit in class javax.crypto.KeyGeneratorSpi

Parameters:

random - the random seed for this generator

engineGenerateKey

protected javax.crypto.SecretKey engineGenerateKey()

Generates a new key.

Specified by:

engineGenerateKey in class javax.crypto.KeyGeneratorSpi

Returns:

the created key