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