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.