Patent ID: 7634663

Claim:
A program falsification preventing method in a sheet processing apparatus which has an inspecting device including at least one detecting means for detecting a feature of a sheet to be fed, determining means for determining a sheet based on the feature of the sheet detected by the detecting means and execution means for executing a process based on the determination result by the determining means and a management device connected to the inspecting device via a communication line to manage the inspecting device, comprising: storing programs of the means of the inspecting device and hash function values by the programs in the management device, storing the hash function values by the programs of the means of the inspecting device in the management device at power-ON time and storing the hash function values by the programs of the means in the inspecting device, calculating a new hash function value by use of a date and hour and the hash function values by the programs of the means of the inspecting device in the management device based on a program inspection request, calculating a new hash function value by use of the date and hour and the hash function values by the programs of the means of the inspecting device at power-ON time in the inspecting device, and determining whether the program is falsified by comparing the new hash function value calculated by the management device with the new hash function value calculated by the inspecting device.