A passive keyless system including a base that selectively allows access to a restricted environment through a base transceiver operating with an encrypted link on first and second frequencies, and a base recording element storing base measured movement history information. Also, a passive keyless device with at least one sensor detects a movement property of the device, a device recording element stores movement history information about the device and reflecting the detected movement property, and a device transceiver communicating with the base transceiver, and transmitting to the base transceiver encrypted security information identifying the device in accordance with a passive keyless protocol and/or the movement history information, and an access request element that causes the device transceiver to request access to the base transceiver. The base uses the base measured movement history information and movement history information when allowing access to the restricted environment.