Smart Card minidrivers are implemented according to the Windows Smart Card Minidriver Specification. The specifications prescribe the version and related capabilities to which a minidriver will conform.
Examle: Smart Card Minidriver Specification, v7.07

Smart card vendors can write card minidrivers to present a consistent interface to their smart card type to the Microsoft Smart Card Base Cryptographic Service Provider (CSP) or Crypto Next Generation (CNG) Key Storage Provider (KSP) and to the Smart Card Management Interface. These card minidrivers plug in to Windows operating system code. The functionality in a card minidriver is narrowly scoped and carefully defined so that the card-dependent code is simple to implement and easy to verify functionally.

The specification provides implementation guidelines for Base CSP and KSP card minidrivers. The latest specification applies to Windows 8 and later operating systems.