Nice vid! Not to be a bitch, but actually it still is a single key system, be it digital rather then mechanical. When I first saw the title I thought it would be something biometric.
I've been using RFID for several years as our apartment building uses a Paxton system. I bought a Paxton reader with wiegand output which makes it easily connectable to my own system. 1 tag for the whole building and my neighbors can't enter my house. When I'm on holiday I can easily activate my neighbors tag if I want him to watch the house.