Patent ID: 11882114
Assignee: KOGA ELECTRONICS CO., LTD.
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method for authenticating an originating-side communication device of a group at a receiving-side communication device of the same group in Internet Protocol (IP) communication, the IP communication being performed in a manner such that a plurality of communication devices of the same group are connected to an IP network through communication lines with unique identification numbers and that each of the plurality of communication devices records the identification numbers of the other communication devices in advance and that the originating-side communication device is uniquely connected to the receiving-side communication device based on the identification number so as to transmit packets between the originating-side and receiving-side communication devices, comprising:
(1) generating a new authentication code at the receiving-side communication device whenever at least one prescribed condition is met;
(2) sending the new authentication code from the receiving-side communication device to the originating-side communication device through the IP network by means of packets of new communication which is not affected by past communication information at each generation of the new authentication code;
(3) overwriting the authentication code on a storage of the originating-side communication device whenever the authentication code is received from the receiving-side communication device through the IP network;
(4) sending packets containing the overwritten authentication code from the originating-side communication device to the receiving-side communication device through the IP network on connection from the originating-side communication device to the receiving-side communication device through the IP network; and
(5) determining at the receiving-side communication device that the originating-side communication device is true when the packets received by the receiving-side communication device through the IP network contain the latest authentication code which has been sent from the receiving-side communication device through the IP network or information derived according to a certain method using the latest authentication code, while determining at the receiving-side communication device that the originating-side communication device is false when the received packets do not contain such latest authentication code and information.