In the future it will be enough to touch or look at the car to open it, as well as any other device with security mechanisms. The human body will be the transmitter of the signals.
The German technology company Ident has developed several prototypes that allow the transmission of small electric current across the surface. In one of them, the signal emission system is in safety glasses. Therefore, it would only start when it is detected that it has the glasses on.
According to the inventors, the system works in 30 nanoamps, so it does not harm the human being.