An image processing apparatus is provided. The image processing apparatus includes a storage configured to store an operating system (OS) of the image processing apparatus, a script file including a program code and a first electronic signature, and an interpreter program provided to execute the program code on the OS; and at least one processor configured to perform an authentication of the first electronic signature with the OS in response to the interpreter program executing the program code on the OS, and selectively permit or block the execution of the program code according to whether the first electronic signature passes or fails to pass the authentication.