Patent ID: 7444561

Claim:
A verifier which remotely checks an integrity of a device connected via a network, the verifier comprising: a calculator which fills free areas in a memory of the device with random numbers based on a prestored memory filling map and generates a local check code used to check the integrity of the memory; an interface which transmits integrity check parameters which are used by the device to generate a remote check code used to check the integrity the memory, to the device, and receives the remote check code from the device; a determiner which detects a remote check code generation time by measuring a difference between a transmission time of the integrity check parameters and a reception time of the remote check code and compares the detected remote check code generation time with a prestored remote check code generation expectation time; and a controller which confirms the integrity of the memory of the device if the remote check code generation time does not exceed the remote check code generation expectation time according to a result of the comparison by the determiner and the local check code matches the remote check code.