Windows 7 interfering with smart cards

Dennis picture Dennis · Mar 18, 2010 · Viewed 10k times · Source

I have an application that uses the PC/SC API to communicate with smart cards. On Windows 7, I get strange results: the data returned from the cards is inconsistent and invalid with certain commands. If I disable the Smart Card Plug and Play service in group policy then everything works fine. Has anyone experienced anything similar? Is there any way to get the smart card plug and play service to play nice? It would be nice to not have to disable it...

Answer

Damien picture Damien · Apr 7, 2010

This is happening because you are using a smart card that supports "plug-and-play" under windows 7. In this situation, Windows 7 will automatically attempt to download and install a "Card Mini Driver" for the card when it is inserted. It sounds like the Card Mini Driver that is getting installed is causing the inconsistent behavior.

The obvious workaround is to use a card that doesn't support "plug-and-play" under windows 7. If this isn't possible, you will need to post additional details about the problems you are seeing, specifically what kind of smart card are you using, and what commands are breaking after the card mini driver is installed?

Technet details on Smart Card Plug and Play in windows 7 can be found here:

http://technet.microsoft.com/en-us/library/dd979547(WS.10).aspx