COMMUNICATION SYSTEM AND COMMUNICATION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a communication system and a communication terminal for performing multi-hop transmissions securely with a small amount of delay. SOLUTION: A communication device includes an authentication key managing means of managing an authentication key; a time-varying parameter managing means of managing a time change parameter for verifying the freshness of a secure communication frame; a reception authentication history managing means of managing reception authentication history information of a secure communication frame; and a communication frame authenticating means of performing authentication processings on the received communication frame by the authentication key and the time change parameter. The communication frame authenticating means determines that a secure communication frame that has succeeded in authentication is a new and valid communication frame, when the time-varying parameter utilized for security conversion of a secure communication frame is determined as being newer than a past value by a prescribed value, in reference to the time-varying parameter managed by the time change parameter managing means; and the secure communication frame is determined as not having been received in the past by the reception authentication history managing means. COPYRIGHT: (C)2011,JPO&INPIT