This is a RSA key factory that transforms RSA key specs into PKCS#11 key objects and vice versa.
To create PKCS#11 private or public keys, the application cannot pass the actual key specs
directly to the factory. It must wrap them into a PKCS11KeySpec, which tells the factory on which
token to generate the key. For private keys this key factory supports RSAPrivateKeySpec,
RSAPrivateCrtKeySpec and PKCS8EncodedKeySpec. For public keys it supports RSAPublicKeySpec and