A system, comprising: a vehicle processing device coupled to a communication bus of a vehicle ; a first security device that includes first unique information that is uniquely associated with the vehicle; a second security device that includes second unique information that is uniquely associated with the vehicle; wherein the vehicle processing device of the vehicle is to: receive a request signal that includes a request to associate a user device with the vehicle; receive a first security signal containing the first unique information from the first security device; receive a second security signal containing the second unique information the second security device; determine that the first security signal was transmitted within a first predetermined range of the vehicle during a first predetermined authentication period that begins after a first authentication trigger event; determine that the second security signal was transmitted within a second predetermined range of the vehicle during a second predetermined authentication period that begins after a second authentication trigger event; and associate the user device with the vehicle when a determination is made that the first unique information was transmitted in the first security signal within the first predetermined range of the vehicle during the first predetermined authentication period, and that that the second security unique information was transmitted in the second security signal within the second predetermined range of the vehicle during the second predetermined authentication period. a vehicle processing device coupled to a communication bus of a vehicle ; a first security device that includes first unique information that is uniquely associated with the vehicle; a second security device that includes second unique information that is uniquely associated with the vehicle; wherein the vehicle processing device of the vehicle is to: receive a request signal that includes a request to associate a user device with the vehicle; receive a first security signal containing the first unique information from the first security device; receive a second security signal containing the second unique information the second security device; determine that the first security signal was transmitted within a first predetermined range of the vehicle during a first predetermined authentication period that begins after a first authentication trigger event; determine that the second security signal was transmitted within a second predetermined range of the vehicle during a second predetermined authentication period that begins after a second authentication trigger event; and receive a request signal that includes a request to associate a user device with the vehicle; receive a first security signal containing the first unique information from the first security device; receive a second security signal containing the second unique information the second security device; determine that the first security signal was transmitted within a first predetermined range of the vehicle during a first predetermined authentication period that begins after a first authentication trigger event; determine that the second security signal was transmitted within a second predetermined range of the vehicle during a second predetermined authentication period that begins after a second authentication trigger event; and associate the user device with the vehicle when a determination is made that the first unique information was transmitted in the first security signal within the first predetermined range of the vehicle during the first predetermined authentication period, and that that the second security unique information was transmitted in the second security signal within the second predetermined range of the vehicle during the second predetermined authentication period. <EOS>