Distance estimation and authentication are provided for Bluetooth systems and devices. Proximity detection requests are transmitted using a transceiver of a tracking device. Reply messages are received from a tracked device. Designated delay values are generated, and round trip times associated with the reply messages are determined based, at least in part, on the designated delay values and time stamps associated with the reply messages. An authenticity metric associated with the tracked device is generated based, at least in part, on the round trip times.