KeyFactorySpi (Java Platform SE 7 b138)

java.lang.Object
- java.security.KeyFactorySpi

```
public abstract class KeyFactorySpi
extends Object
```
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.

Since:

1.2

See Also:
KeyFactory, Key, PublicKey, PrivateKey, KeySpec, DSAPublicKeySpec, X509EncodedKeySpec

Constructor Summary

Constructors
Constructor and Description

KeyFactorySpi()

Constructors
Constructor and Description
`KeyFactorySpi()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected abstract PrivateKey`	`engineGeneratePrivate(KeySpec keySpec)` Generates a private key object from the provided key specification (key material).
`protected abstract PublicKey`	`engineGeneratePublic(KeySpec keySpec)` Generates a public key object from the provided key specification (key material).
`protected abstract <T extends KeySpec> T`	`engineGetKeySpec(Key key, Class<T> keySpec)` Returns a specification (key material) of the given key object.
`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.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - KeyFactorySpi
```
public KeyFactorySpi()
```
- Method Detail
  - engineGeneratePublic
```
protected abstract PublicKey engineGeneratePublic(KeySpec keySpec)
                                           throws InvalidKeySpecException
```
    Generates a public key object from the provided key specification (key material).
    
    Parameters:
    keySpec - the specification (key material) of the public key.
    
    Returns:
    the public key.
    
    Throws:
    
    InvalidKeySpecException - if the given key specification is inappropriate for this key factory to produce a public key.
  - engineGeneratePrivate
```
protected abstract PrivateKey engineGeneratePrivate(KeySpec keySpec)
                                             throws InvalidKeySpecException
```
    Generates a private key object from the provided key specification (key material).
    
    Parameters:
    keySpec - the specification (key material) of the private key.
    
    Returns:
    the private key.
    
    Throws:
    
    InvalidKeySpecException - if the given key specification is inappropriate for this key factory to produce a private key.
  - engineGetKeySpec
```
protected abstract <T extends KeySpec> T engineGetKeySpec(Key key,
                                     Class<T> keySpec)
                                               throws InvalidKeySpecException
```
    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 - the key.
    keySpec - the specification class in which the key material should be returned.
    
    Returns:
    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
```
protected abstract Key engineTranslateKey(Key key)
                                   throws InvalidKeyException
```
    Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.
    
    Parameters:
    key - the key whose provider is unknown or untrusted.
    
    Returns:
    the translated key.
    
    Throws:
    
    InvalidKeyException - if the given key cannot be processed by this key factory.

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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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DRAFT ea-b138

Class KeyFactorySpi

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

KeyFactorySpi

Method Detail

engineGeneratePublic

engineGeneratePrivate

engineGetKeySpec

engineTranslateKey