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

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

KeyFactorySpi

Added in API level 1

public KeyFactorySpi ()

Protected methods

engineGeneratePrivate

Added in API level 1

protected abstract 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

protected abstract 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

protected abstract 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

protected 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.

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.