Presence-triggered beacon authentication

A system and method for authenticating a user of a device includes a user fob configured to transmit a code related to authentication, wherein the device is configured to receive the transmitted code and confirm that the holder of the fob is or is not an authorized user. In an embodiment, the device is configured to detect a user presence before checking for receipt of a transmitted code. In a further embodiment, the device is configured to emit a beacon upon detecting a user presence, prompting the user fob to transmit the code. The beacon medium may be IR (infrared), ultrasound or other low power medium, and similarly, the fob may detect the beacon and/or transmit the code in any suitable medium including IR and ultrasound.