A method of controlling a vehicle that includes a plurality of electronic control units (ECUs), the method including: allocating an order in which at least one ECU among the plurality of ECUs is to be assigned an encryption key, based on a data rate of each ECU; receiving, by the at least one ECU, at least one encryption key that is assigned to the at least one ECU according to the allocated order; and performing, by the at least one ECU and using the assigned at least one encryption key, (i) encryption of data to be transmitted through a Controller Area Network (CAN) communication bus, or (ii) decryption of data that is transmitted through the CAN communication bus.