Smart card with an integrated electrical switch for secure operation

Security concerns and privacy infringement can be serious problems in many applications of radio frequency identification (RFID) systems. Most of the problems are due to the lack of user control over the communication between RFID tags and readers. Giving the user control over the RFID link can alleviate potential security problems. A simple smart card that prevents unauthorized credit card payment or unwanted identification theft can be realized by integrating a simple electrical touch switch with a 14443 smart card. The smart card is activated only when the user touches the switch; specifically, the impedance of an interdigitated capacitor changes at the touch of a finger.