The position information use manner in the position information service system, and the position information service system, the master station, through position center, and

摘要

PROBLEM TO BE SOLVED: To provide a position information service system which makes the ID of an originating terminal secret to the outside of an exchange network, provides information at a request from a terminating terminal unlimited to a special number, and charges the terminal on a renotification non-charging basis. ;SOLUTION: To cipher position information by using a key which is updated at intervals of unit time, the originating terminal generates a work key for ciphering by using the update time and information identifying a sender and ciphers the position information by using the work key for ciphering and a terminating terminal number. The terminating terminal caches corresponding position information and ciphered position information in pairs and acquires ciphered position information from a position center if no cache hit is made. The terminating terminal is charged at a request to decipher which is sent to the position center. The cache is cleared in the timing of the update of the unit time.;COPYRIGHT: (C)2001,JPO