Display configured to display various information and method of controlling the display

A method of controlling a display device configured to output various information, wherein

• the method is performed by the display device comprising a display facing an outside of a vehicle and configured to output a sign corresponding to at least one of various pieces of information and a processor configured to output the sign or transmit, receive, or process an authentication request or an authentication result for the at least one of the various pieces of information, the method comprising:
• transmitting the authentication request for the at least one of the various pieces of information related to an owner, a driver, or an occupant of the vehicle to an authentication server or an authentication application;
• receiving the authentication result;
• and
• controlling the display to output the sign according to the received authentication result.