A chip mountable on a customer replaceable unit monitoring memory (CRUM) unit used in an image forming job includes a central processing unit (CPU) with its own operating system (OS), which operates separately from an OS of the image forming apparatus, to perform authentication communication with a main body of the image forming apparatus using the OS of the CPU. The security of a unit on which the chip is mounted can thereby be reinforced and random changes of data of the unit can be prevented.