METHOD FOR FINDING REPLICATED TERMINAL

摘要

PROBLEM TO BE SOLVED: To automatically find and exclude a replicated terminal in a communication system, consisting of a center and a plurality of terminals. SOLUTION: The center and a plurality of the terminal are connected through a communication network for ciphering communication with individual session keys. The center sends challenge information in the case of delivering a new session key to the terminals. Each of the terminals sends response information obtained by ciphering terminal ID and a terminal random number to a center public key to the center, which retrieves a communication log and inspects the presence/absence of terminals, having the same terminal ID and different terminal random numbers. If corresponding terminals exist, it decides that the replicated terminal exists, and the session key will not be delivered. Since random number generated by an original terminal is difficult to replicate, the replicated terminals cannot generate the same random number. Thus, the existence of the replicated terminal can be detected.