Microchip introduced at the embedded world in Nuernberg a new development kit: the BodyCom. It uses small tags with which it communicates over the body impedance by using signals transferred via capacity.
The human body acts in this case as a secure channel which transfers the signal safely to e.g. an opening system. The existing wireless cards have the strong disadvantage that a potential attacker can receive the signal as well and use it afterwards to enter e.g. a car.