Patent ID: 8863238

Claim:
A mutual authentication system comprising: a higher-level device and a lower-level device that mutually authenticate each other; wherein the lower-level device includes: a control unit configured to control the lower-level device; and a plurality of slave devices controlled by the control unit; wherein the control unit includes: an authentication management unit configured to transmit information to, and receive information from, the higher-level device and each of the plurality of slave devices to mutually authenticate each other; wherein the plurality of slave devices individually include: an authentication processing unit configured to create lower-level authentication information for authenticating the higher-level device; and a memory unit configured to save the lower-level authentication information; and wherein the authentication management unit includes: a commanding means for commanding one of the plurality of slave devices to create the lower-level authentication information, according to a request on authentication from the higher-level device; a sharing means for transmitting the lower-level authentication information received from the above-mentioned one of the slave devices, to the other of the slave devices for the purpose of sharing the lower-level authentication information; and a transmission means for transmitting the lower-level authentication information, having been shared in all the plurality of slave devices, to the higher-level device.