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 bi-directional.
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. Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.