Patent ID: 7941832

Claim:
An authentication device in an authentication system including a plurality of authentication devices, the authentication device comprising: a nonvolatile memory configured to store one of a plurality of divided data blocks obtained by dividing into multiple data blocks authentication data which has been prepared in advance for executing authentication through cross-checking against input data input to the authentication device; a receiver configured to receive a divided data block stored in another authentication device; a reconstituting module that assembles the divided data block stored in the nonvolatile memory to the received divided data block and reconstitutes the authentication data; a volatile memory configured to store the reconstituted authentication data; an authentication module that authenticates by cross-checking the reconstituted authentication data against the input data input to the authentication device at the time of authentication; a dividing module that re-divides the reconstituted authentication data into divided data blocks different from the divided data blocks prior to reconstitution; and a distributor portion configured to distribute the re-divided data blocks to other authentication devices, wherein: no non-divided authentication data is stored in any authentication device in the authentication system, and the authentication device further comprises: a cross-checking module that cross-checks first authentication data reconstituted by the reconstituting module during a first time period and stored in the nonvolatile memory, against second authentication data reconstituted by the reconstituting module during a second time period subsequent to the first time period, the first time period being a startup time of the authentication device; and an alarm configured to issue an alert in the event that the first authentication data and the second authentication data do not match with each other.