A smart key configured to control a plurality of vehicles includes: a first communication unit configured to exchange information with the plurality of vehicles; an information acquisition device configured to acquire user information associated with a user of the smart key; at least one processor; and a computer-readable medium coupled to the at least one processor having stored thereon instructions which, when executed by the at least one processor, causes the at least one processor to perform operations including: based on the user information, selecting, as a vehicle to enter, at least one vehicle among the plurality of vehicles based on the user information and based on information associated with the plurality of vehicles; and exchanging, through the first communication unit, a signal with the selected at least one vehicle.