MOBILE COMMUNICATION TERMINAL AND NETWORK CONNECTION APPARATUS IN MOBILE COMMUNICATION NETWORK SYSTEM, AND UPDATE METHOD OF SHARED PRIVATE KEY, AND UPDATE PROGRAM OF SHARED PRIVATE KEY

摘要

PROBLEM TO BE SOLVED: To provide an update method and means for shared private key that can be applicable even in the case that a mobile communication terminal changes a network connection apparatus being a communication opposite party by handover and can update the shared private key used for communication at each prescribed time. SOLUTION: Counters 1, 2, 3 for counting a lapse of time after a control purpose shared private key 26 and a communication purpose shared private key 22 are generated, are arranged. In the case of carrying out the handover, the control purpose shared key 26, the communication purpose shared private key 22 and the count of the counter 2 are exchanged between access routers AR11 and AR12. Thus, even on the occurrence of the handover, the communication purpose shared private key 22 can be updated by the control purpose shared private key 26 at each prescribed time and interpretation of the communication purpose shared private key 22 by a third party can be prevented. COPYRIGHT: (C)2005,JPO&NCIPI