The Card Bank is an inventory of cards associated with an account. It indicates which cards are assigned to users and which cards are unassigned. (Unassigned cards do not allow any type of access to a site.)

Cards can be assigned, revoked or deleted. When a card is assigned, it allows a user access to a site and one or more of its doors. When a card is revoked from a user, it becomes unassigned and can be assigned later to another user. When a card is deleted, it is erased from the account. If deemed appropriate (i.e. a card reported lost or destroyed is later recovered), deleted cards may be recreated.