| 摘要 |
PROBLEM TO BE SOLVED: To provide an unauthorized rewrite detection circuit that does not access a memory, wherein circuit data of a programmable logic device is stored, and shortens a power supply time of the programmable logic device required for unauthorized rewrite detection for circuit data, and to provide an image forming apparatus.SOLUTION: The unauthorized rewrite detection circuit includes: a first memory 4 wherein state definition information for defining a state of a terminal T of a programmable logic device 2 and circuit data are stored; the programmable logic device 2; a power supply unit 11 which supplies driving power to the programmable logic device 2; a terminal state detection unit 12 which detects the state of the terminal T; a second memory 14 wherein state information indicating a state in which the terminal should be immediately after reading-in of the circuit data by the programmable logic device 2 is preliminarily stored; and a control unit 10 which detects unauthorized rewrite of the circuit data when the state of the terminal detected by the terminal state detection unit 12 is different from the state information stored in the second memory 14. |
