Secure LED based on microcontroller avr is an optical access control device which replaces current RFID or Magnetic Strip technologies with a cryptographically secure, contact-less device which communicates over commodity Light Emitting Diodes (LEDs).
Marcin Bojanczyk, Chris Danis and Brian Rogan from Cornell University have tried another acces controll methode based one Light Emitting Diode. This project started with one central premise: current physical access control systems are insecure in fundamental ways. They sought a way to remedy this problem, and came accross recent work which demonstrated the potential of communicating over cheap commodity LEDs. They used these as the basis of their system, building on top of it devices which use a cryptographically secure challenge-response protocol to authenciate a user.
As such, they built both a reader and a small key device. The reader outputs the industry-standard Weigand protocol, so it is interoperable with current systems. All in all, they believe that this solution presents a powerful alternative to current technology.
Link: Cornell University