Patent ID: 8069477
Filing Date: 2011-11-29
Classification: G03G,G06F,H04L,H04N

Abstract:
1. A customer replaceable unit monitoring (CRUM) unit usable in a replaceable unit which is mountable in an image forming apparatus and capable of performing an image forming operation with a main body of the image forming apparatus, the CRUM unit comprising: a memory unit storing a second initialization program different from a first initialization program used in the main body of the image forming apparatus, unique information associated with the replaceable unit, and status information on use of the replaceable unit; and a central processing unit (CPU) coupled to the memory unit, wherein, if initialization is required, the CPU performs the initialization using the second initialization program independently from the main body, and if a first number is received from the main body of the image forming apparatus, the CPU generates a second number, generates a first message authentication code (MAC) using the first number and the second number, and transmits the second number and the first MAC to the main body, wherein, if the main body generates a second MAC using the first number and the second number and performs an authentication process of the CRUM unit by comparing the second MAC with the first MAC, the CPU updates the status information stored in the memory unit by performing cryptographic data communication with the main body to receive a communication message including encrypted communication data and a third MAC from the main body.