KeyFactorySpi (Java Platform SE 8 ) (original) (raw)

• 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 usingDSAPublicKeySpec orX509EncodedKeySpec. 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	Description
  KeyFactorySpi()

  • Method Summary

  All Methods Instance Methods Abstract Methods

  Modifier and Type	Method	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 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](../../java/lang/Object.html "class in java.lang")  
     `[clone](../../java/lang/Object.html#clone--), [equals](../../java/lang/Object.html#equals-java.lang.Object-), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [hashCode](../../java/lang/Object.html#hashCode--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [toString](../../java/lang/Object.html#toString--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`

• • Constructor Detail

     * #### KeyFactorySpi  
     public KeyFactorySpi()  

  • Method Detail

    * #### engineGeneratePublic  
    protected abstract [PublicKey](../../java/security/PublicKey.html "interface in java.security") engineGeneratePublic([KeySpec](../../java/security/spec/KeySpec.html "interface in java.security.spec") keySpec)  
                                               throws [InvalidKeySpecException](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")  
    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](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")` \- if the given key specification is inappropriate for this key factory to produce a public key.  
    * #### engineGeneratePrivate  
    protected abstract [PrivateKey](../../java/security/PrivateKey.html "interface in java.security") engineGeneratePrivate([KeySpec](../../java/security/spec/KeySpec.html "interface in java.security.spec") keySpec)  
                                                 throws [InvalidKeySpecException](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")  
    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](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")` \- if the given key specification is inappropriate for this key factory to produce a private key.  
    * #### engineGetKeySpec  
    protected abstract <T extends [KeySpec](../../java/security/spec/KeySpec.html "interface in java.security.spec")> T engineGetKeySpec([Key](../../java/security/Key.html "interface in java.security") key,  
                                                              [Class](../../java/lang/Class.html "class in java.lang")<T> keySpec)  
                                                       throws [InvalidKeySpecException](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")  
    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.  
    Type Parameters:  
    `T` \- the type of the key specification to be returned  
    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](../../java/security/spec/InvalidKeySpecException.html "class in java.security.spec")` \- 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](../../java/security/Key.html "interface in java.security") engineTranslateKey([Key](../../java/security/Key.html "interface in java.security") key)  
                                       throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")  
    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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key cannot be processed by this key factory.

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