| 摘要 |
PROBLEM TO BE SOLVED: To realize safe communication even if a moving computer moves to any place on a network by obtaining a position on the network of a packet relay device denying passage from a return message and adding a negotiation message code. SOLUTION: The moving computer 2 does not recognize peripheral network environment when it is reconnected to a moving destination network and it transmits the packet of a plain sentence to a communication opposite party. A gateway GW 1 returns an error message to the moving computer 2 since a negotiation code required for passing through the gateway GW 1 is not added to the packet. Necessary key information is exchanged between the moving computer 2 and the gateway GW 1 and the negotiation code between routes is calculated. When the inner packet is ciphered from the moving computer 2 and the packet to which the negotiation code is added is returned to the gateway GW 1, the packet can pass through the gateway GW 1. |
