PKCS11 is an API used by smartcards and Hardware Security Modules to perform
cryptographic operations such as signature or encryption.

This library contains two parts: type definitions corresponding to the PKCS#11
API, and bindings using ctypes to emit calls to a DLL.

To install the driver part, install ctypes and ctypes-foreign - it will
build a pkcs11.driver package.

The entry point of this library is [P11.load_driver]. An example is available in
test/example_sign.ml.