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KeyFactorySpi

public abstract class KeyFactorySpi
extends Object

java.lang.Object
   ↳ java.security.KeyFactorySpi


This class defines the Service Provider Interface (SPI) for the KeyFactory class. All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a key factory for a particular algorithm.

Key factories are used to convert keys (opaque cryptographic keys of type Key) into key specifications (transparent representations of the underlying key material), and vice versa.

Key factories are bi-directional. That is, they allow you to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.

Multiple compatible key specifications may exist for the same key. For example, a DSA public key may be specified using DSAPublicKeySpec or X509EncodedKeySpec. A key factory can be used to translate between compatible key specifications.

A provider should document all the key specifications supported by its key factory.

See also:

Summary

Public constructors

KeyFactorySpi()

Protected methods

abstract PrivateKey engineGeneratePrivate(KeySpec keySpec)

Generates a private key object from the provided key specification (key material).

abstract PublicKey engineGeneratePublic(KeySpec keySpec)

Generates a public key object from the provided key specification (key material).

abstract <T extends KeySpec> T engineGetKeySpec(Key key, Class<T> keySpec)

Returns a specification (key material) of the given key object.

abstract Key engineTranslateKey(Key key)

Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.

Inherited methods

From class java.lang.Object

Public constructors

KeyFactorySpi

Added in API level 1
KeyFactorySpi ()

Protected methods

engineGeneratePrivate

Added in API level 1
PrivateKey engineGeneratePrivate (KeySpec keySpec)

Generates a private key object from the provided key specification (key material).

Parameters
keySpec KeySpec: the specification (key material) of the private key.
Returns
PrivateKey the private key.
Throws
InvalidKeySpecException if the given key specification is inappropriate for this key factory to produce a private key.

engineGeneratePublic

Added in API level 1
PublicKey engineGeneratePublic (KeySpec keySpec)

Generates a public key object from the provided key specification (key material).

Parameters
keySpec KeySpec: the specification (key material) of the public key.
Returns
PublicKey the public key.
Throws
InvalidKeySpecException if the given key specification is inappropriate for this key factory to produce a public key.

engineGetKeySpec

Added in API level 1
T engineGetKeySpec (Key key, 
                Class<T> keySpec)

Returns a specification (key material) of the given key object. keySpec identifies the specification class in which the key material should be returned. It could, for example, be DSAPublicKeySpec.class, to indicate that the key material should be returned in an instance of the DSAPublicKeySpec class.

Parameters
key Key: the key.
keySpec Class: the specification class in which the key material should be returned.
Returns
T the underlying key specification (key material) in an instance of the requested specification class.
Throws
InvalidKeySpecException if the requested key specification is inappropriate for the given key, or the given key cannot be dealt with (e.g., the given key has an unrecognized format).

engineTranslateKey

Added in API level 1
Key engineTranslateKey (Key key)

Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.

Parameters
key Key: the key whose provider is unknown or untrusted.
Returns
Key the translated key.
Throws
InvalidKeyException if the given key cannot be processed by this key factory.
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