Find Smart Card Mini-Driver Registration in Regedit

This article explains the exact Windows Registry locations used to store registration details for system-level cryptographic smart card mini-drivers. It details the primary registry keys for both 64-bit and 32-bit subsystems, explains the critical values used by the Windows Cryptographic Architecture to pair cards with their drivers, and provides a direct path to inspecting your installed smart card modules.

Primary Smart Card Mini-Driver Registry Path

In the Windows Registry (regedit.exe), system-level cryptographic smart card mini-drivers are cataloged under the “Calais” cryptographic subsystem.

The primary location for registered smart card mini-drivers is:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Calais\SmartCards

For 32-bit applications running on 64-bit Windows operating systems, the registry path is mirrored under the WOW64 node:

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Cryptography\Calais\SmartCards

Structure of a Smart Card Registration Key

Inside the SmartCards key, each supported smart card has its own dedicated subkey, typically named after the card model or manufacturer (for example, Identity Card (PKI) or a vendor-specific card name).

Each subkey contains the following configuration values:

• 80000001 (REG_SZ): Specifies the filename or full path of the Smart Card Mini-Driver DLL module (e.g., msclmd.dll or a third-party mini-driver DLL).
• ATR (REG_BINARY): The Answer-to-Reset byte sequence that uniquely identifies the card hardware.
• ATRMask (REG_BINARY): A bitmask used alongside the ATR to match the specific card when inserted into a reader.
• Crypto Provider (REG_SZ): The legacy CryptoAPI Cryptographic Service Provider (CSP) associated with the card (commonly Microsoft Base Smart Card Crypto Provider).
• Smart Card Key Storage Provider (REG_SZ): The Cryptography Next Generation (CNG) Key Storage Provider (KSP) associated with the card (typically Microsoft Smart Card Key Storage Provider).

Related Registry Locations

Depending on the driver architecture and subsystem components, additional cryptographic settings are located in these related registry keys:

1. Cryptography Next Generation (CNG) Providers

To view the registration of the CNG Key Storage Providers that interact with smart card mini-drivers:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Cryptography\Providers

2. Smart Card Readers

To inspect the readers registered with the Calais subsystem:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Calais\Readers

How to Inspect the Mini-Driver Details

1. Press Windows Key + R, type regedit, and press Enter.
2. Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Calais\SmartCards
3. Expand the SmartCards key and select the subkey corresponding to your target card.
4. Check the 80000001 entry in the right-hand pane to find the active mini-driver DLL file name.