How are PCSC smart card reader 'friendly names' constructed?

4
votes

I use WinSCard to list all readers, which gives me a list like this:

ASK RDR4x7 0
SCM Microsystems Inc. SCR3320 USB Smart Card Reader 0
SCM Microsystems Inc. SCR3320 USB Smart Card Reader 1
SCM Microsystems Inc. SCR3320 USB Smart Card Reader 2

Which is great, but I have no clue which name belongs to which card reader.

Where do these names come from? How are they constructed?

What I've found up until now: in the registry, there is a HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services key. Under this key, you can find the subkey which matches the card reader's "service" (which I found by querying the WMI registry). For example: the service for the SCM Microsystems Inc. SCR3320 USB Smart Card Reader readers is SCR3XX2K.

This subkey (SCR3XX2K) has another subkey Enum, which has multiple interesting values:

  • Count: DWORD, the number of readers connected
  • 0, 1, 2: STRING, hardware Device ID

I guess these are the numbers appended to the 'friendly names', but I can't figure out how the name string is constructed. I need this to map hardware Device ID's (which I get through WMI) to their friendly name.

So, what's the pattern used to create a 'friendly name' for a smart card reader, and where do the values come from?

1
c#.netsmartcard-readerpcscwinscard

1 Answers

8
votes

They are a concatination of these 3 attributes:

SCARD_ATTR_VENDOR_NAME
SCARD_ATTR_VENDOR_IFD_TYPE
SCARD_ATTR_DEVICE_UNIT

The TechNet article Smart Card Events documents this in the "Smart Card reader name" section.

SCARD_??? attributes are requested with the SCardGetAttrib function.

The SCARD_ATTR_DEVICE_SYSTEM_NAME attribute returns the friendly name as the ones you get while listing the readers.

The list of SmartCard readers exists in the registry under HKLM\SOFTWARE\Microsoft\Cryptography\Calais\Readers. Readers are added to this list by the INF file of the SCR driver, so during driver installation.

A link between device and reader can be found in the SmartCardReader class {50DD5230-BA8A-11D1-BF5D-0000F805F530} under HKLM\SYSTEM\CurrentControlSet\Control\Class\{50DD5230-BA8A-11D1-BF5D-0000F805F5‌​30}.