When you want to write test cases on Any Application, then prepare a check list for that application/Function/Etc...
Writing Test cases on Smart Card, please take out following things from REQUIREMENT/SPECIFICATION/FUNCTIONAL/DESIGN DOCUMENTS
1. What is Smart Card?
2. Why we use Smart Card?
3. Who are eligible for Smart Card, If System generate this?
4. How it validate the user, i.e., Swapping/punching/etc...
5. What are the ways to use this Card?
6. How can be a Card deactivated?
7. How many no. of trial is permissible by a trial at a time or a day.
8. If user is accessing this by punching password then how many trials are pemissible?
9. If it is inserted in the manchine or swap in the machine then can we use other material than listed material, like paper, iron, Plastic of same weight and size...
10. If system generate a duplicate card (if some one lost a card) then is it deactivate lost card and cerate new card of same Card # with some extra information or create a completely new card.
11. When we create a duplicate card then what information is required?
12. After deactivation can we use deactivated card?
13. How many users can access such facility at a time (Performance Testing)?
14. Test UAT.
15. Validation testing.
16. Volume testing.
And many other things to be covered in this as per the requirement.