Abstract: An apparatus or method for authenticating a user's access to a device such as, for example, a garage. In one embodiment, the method includes a first device receiving an activation signal directly or indirectly from a user. The first device transmits a first signal to a second device in response to receiving the activation signal. The second device is coupled to a motor that opens or closes a door of the garage. In response to receiving the first signal, the second device transmits a second signal to the first device, wherein the second signal includes a randomly generated number. The first device encrypts the randomly generated number received from the second device to generate a first encrypted number. Thereafter the first device transmits a third signal to the second device, wherein the third signal includes the first encrypted number. In addition to sending the randomly generated number to the first device, the second device encrypts the randomly generated number to generate a second encrypted number.