iaik.security.elgamal

Class ElGamalKeyFactory

java.lang.Object

java.security.KeyFactorySpi

iaik.security.elgamal.ElGamalKeyFactory

public final class ElGamalKeyFactory
extends java.security.KeyFactorySpi

This class converts ElGamal keys (opaque representation) in their KeySpecs (transparent representation) and vice versa.

• ElGamalPublicKey <--> ElGamalPublicKeySpec or X509EncodedKeySpec
• ElGamalPrivateKey <--> ElGamalPrivateKeySpec or PKCS8EncodedKeySpec

To convert, for instance, DER encoded PKCS#8 private key material (e.g. pkcs8_key_spec instantiated from PKCS8EncodedKeySpec) into ElGamalPrivateKey representation, use this KeyFactory for ElGamal keys:

 KeyFactory ElGamal_key_fac = KeyFactory.getInstance("ElGamal");
 ElGamalPrivateKey ElGamal_priv_key = (ElGamalPrivateKey)ElGamal_key_fac.generatePrivate(pkcs8_key_spec);
 

Version:

File Revision 15

See Also:

ElGamalPrivateKey, ElGamalPublicKey

Constructor Summary

Constructors

Constructor and Description
ElGamalKeyFactory() Default constructor for creating a ElGamalKeyFactory.

Method Summary

Methods

Modifier and Type	Method and Description
protected java.security.PrivateKey	engineGeneratePrivate(java.security.spec.KeySpec keySpec) Converts the given key specification to a PrivateKey.
protected java.security.PublicKey	engineGeneratePublic(java.security.spec.KeySpec keySpec) Converts the given key specification to a PublicKey.
protected java.security.spec.KeySpec	engineGetKeySpec(java.security.Key key, java.lang.Class classSpec) Converts the given key into the requested key specification (key material).
protected java.security.Key	engineTranslateKey(java.security.Key key) Translates the given key object of some unknown or untrusted provider into a key object supported by this ElGamal key factory.

Methods inherited from class java.lang.Object

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

Constructor Detail

ElGamalKeyFactory

public ElGamalKeyFactory()

Default constructor for creating a ElGamalKeyFactory. Applications shall use KeyFactory.getInstance("ElGamal"); for instantiating a ElGamalKeyFactory.

Method Detail

engineGeneratePrivate

protected java.security.PrivateKey engineGeneratePrivate(java.security.spec.KeySpec keySpec)
                                                  throws java.security.spec.InvalidKeySpecException

Converts the given key specification to a PrivateKey. The given key material may either be a ElGamalPrivateKeySpec or a PKCS8EncodedKeySpec.

Specified by:

engineGeneratePrivate in class java.security.KeyFactorySpi

Parameters:

keySpec - the key specification as ElGamalPrivateKeySpec or PKCS8EncodedKeySpec

Returns:

the resulting PrivateKey

Throws:

java.security.spec.InvalidKeySpecException - if the given key material is not a ElGamalPrivateKeySpec or PKCS8EncodedKeySpec

engineGeneratePublic

protected java.security.PublicKey engineGeneratePublic(java.security.spec.KeySpec keySpec)
                                                throws java.security.spec.InvalidKeySpecException

Converts the given key specification to a PublicKey. The given key material may either be a ElGamalPublicKeySpec or a X509EncodedKeySpec.

Specified by:

engineGeneratePublic in class java.security.KeyFactorySpi

Parameters:

keySpec - the key specification as ElGamalPublicKeySpec or X509EncodedKeySpec

Returns:

the resulting PublicKey

Throws:

java.security.spec.InvalidKeySpecException - if the given key material is not a ElGamalPublicKeySpec or X509EncodedKeySpec

engineGetKeySpec

protected java.security.spec.KeySpec engineGetKeySpec(java.security.Key key,
                                          java.lang.Class classSpec)
                                               throws java.security.spec.InvalidKeySpecException

Converts the given key into the requested key specification (key material). The given key may either be a ElGamalPublicKey or a ElGamalPrivateKey. If the key is a ElGamalPublicKey, this method only can create a ElGamalPublicKeySpec or a X509EncodedKeySpec from it. If the given key is a ElGamalPrivateKey, a ElGamalPrivateKeySpec or a PKCS8EncodedKeySpec may be returned, depending on which of these two types of specifications is requested by classSpec. Each attempt to get key material of a type not matching to a given ElGamal key will raise an exception.

Specified by:

engineGetKeySpec in class java.security.KeyFactorySpi

Parameters:

key - the key to be converted, which either may be a ElGamalPublicKey or a ElGamalPrivateKey.

classSpec - the key specification type into which the key shall be converted, which may be a ElGamalPublicKeySpec or a X509EncodedKeySpec if the given key is a ElGamalPublicKey, or a ElGamalPrivateKeySpec or a PKCS8EncodedKeySpec if the given key is a ElGamalPrivateKey

Returns:

the key specification (key material) derived from the given key

Throws:

java.security.spec.InvalidKeySpecException - if the given key cannot be converted into the requested key specification object by this key factory

engineTranslateKey

protected java.security.Key engineTranslateKey(java.security.Key key)
                                        throws java.security.InvalidKeyException

Translates the given key object of some unknown or untrusted provider into a key object supported by this ElGamal key factory. This method only can translate keys of type ElGamalPublicKey or ElGamalPrivateKey.

Specified by:

engineTranslateKey in class java.security.KeyFactorySpi

Parameters:

key - the key of some unknown or untrusted provider

Returns:

the translated key

Throws:

java.security.InvalidKeyException - if the given key cannot be translated by this key factory