Systems and methods are described for a display driver integrated circuit that is configured to certify whether an application processor and the display driver integrated circuit are genuine products. The display driver integrated circuit includes: an encryptor for generating first encrypted data by encrypting first data; a data converter for converting the first data into a first converted signal expressed with four or more voltage levels; an interface for providing the first converted signal to a host processor, and receiving, from the host processor, a second converted signal corresponding to second encrypted data generated by the host processor; and a determiner for controlling a display panel by comparing the first encrypted data with converted data corresponding to the second encrypted data. The second converted signal transferred through the interface is expressed with the voltage levels.