Terminal Identification Method, Authentication Method, Authentication System, Server, Terminal, Wireless Base Station, Program, and Recording Medium

A terminal identification method for identifying at least terminal in communication via a network between a server and the terminal, the method comprising:

• sharing a first hash function H and an initial value S(k, 0) which is determined for each terminal between the server and the terminal;
• calculating a temporary ID at the server and the terminal based on a value S(k, i) which is obtained by hashing the initial value S(k, 0) i times with the first hash function H, or by performing a calculation using the initial value S(k, 0), a parameter i, and the first hash function H;
• and
• calculating the same temporary ID at the server and the terminal by setting the same number of times of hashing operations at the server and the terminal to identify the terminal using the temporary ID.

A server which communicates with a terminal connected therewith via a network, comprising:

• a memory unit which holds an initial value S(k, 0) which is identical to an initial value held by the terminal;
• and
• a temporary ID calculating unit which calculates a temporary ID based on a value S(k, i) obtained:
• by applying a hash function H to the initial value S(k, 0) held in the memory unit, the same i times as the number of times of hashing operations at the terminal;
• or by applying a calculation which is identical to a calculation carried out at the terminal based on the initial value S(k, 0), a parameter i, and the hash function H,
• wherein the server identifies the terminal using the temporary ID calculated by the temporary ID calculating unit.

A terminal which communicates with a server connected therewith via a network, comprising:

• a memory unit which holds an initial value S(k, 0) which is identical to an initial value held by the server;
• and
• a temporary ID calculating unit which calculates a temporary ID based on a value S(k, i) obtained:
• by applying a hash function H to the initial value S(k, 0) held in the memory unit, the same i times as the number of times of hashing operations at the server;
• or by applying a calculation which is identical to a calculation carried out at the server based on the initial value S(k, 0), a parameter i, and the hash function H,
• wherein the terminal communicates with the server using the temporary ID calculated by the temporary ID calculating unit.

An authentication method used in communication between a server and a terminal, comprising:

• holding, at the server and the terminal, a hash function and authentication information in common;
• acquiring, at the server and the terminal, a communication parameter which is temporarily common during the communication between the server and the terminal as an authenticating communication parameter;
• generating, at the server and the terminal, an authentication key using the hash function based on the authentication information and the authenticating communication parameter;
• and
• carrying out, at least at one of the server and the terminal, authentication between the server and the terminal using the authentication key which has been generated.

An authentication system in which a terminal and a server make authentication via a wireless base station, the terminal and the wireless base station make wireless communication with each other, and the server and the terminal hold a hash function and authentication information in common, wherein

• the terminal comprises:
• a terminal side authentication parameter acquiring unit which acquires, as an authenticating communication parameter, a communication parameter which is temporarily common during communication between the terminal and the wireless base station;
• a terminal side authentication key generating unit which generates a first authentication key based on the authenticating communication parameter acquired by the terminal side authentication parameter acquiring unit, the authentication information, and the hash function;
• and
• a terminal side authentication key sending unit which sends the first authentication key via the wireless base station to the server,
• the wireless base station comprises:
• a wireless base station side authentication parameter acquiring unit which acquires, as an authenticating communication parameter, a communication parameter which is temporarily common during communication between the terminal and the wireless base station;
• and
• a forwarding unit which attaches the authenticating communication parameter acquired by the wireless base station side authentication parameter acquiring unit to the first authentication key sent by the terminal, and sends the authenticating communication parameter and the first authentication key to the server, and
• the server comprises:
• a server side receiving unit which receives the first authentication key with the authenticating communication parameter attached thereto from the wireless base station;
• a server side authentication key generating unit which generates a second authentication key based on the authenticating communication parameter received by the server side receiving unit, the authentication information, and the hash function;
• and
• a server side authenticating unit which authenticates the terminal by determining whether the second authentication key which has been generated and the first authentication key which has been received are identical.

A terminal used in an authentication system in which the terminal and a server make authentication via a wireless base station, the terminal and the wireless base station make wireless communication with each other, and the server and the terminal hold a hash function and authentication information in common, comprising:

• a terminal side authentication parameter acquiring unit which acquires, as an authenticating communication parameter, a communication parameter which is temporarily common during communication with the wireless base station;
• a terminal side authentication key generating unit which generates a first authentication key based on the authenticating communication parameter acquired by the terminal side authentication parameter acquiring unit, the authentication information, and the hash function;
• and
• a terminal side authentication key sending unit which sends the first authentication key via the wireless base station to the server.

A server used in an authentication system in which a terminal and the server make authentication via a wireless base station, the terminal and the wireless base station make wireless communication with each other, and the server and the terminal hold a hash function and authentication information in common, comprising:

• a server side receiving unit which receives a first authentication key with an authenticating communication parameter attached thereto from the wireless base station;
• a server side authentication key generating unit which generates a second authentication key based on the authenticating communication parameter received by the server side receiving unit, the authentication information, and the hash function;
• and
• a server side authenticating unit which authenticates the terminal by determining whether the second authentication key which has been generated and the first authentication key which has been received are identical.

A program executed by a computer of a terminal used in an authentication system in which the terminal and a server make authentication via a wireless base station, the terminal and the wireless base station make wireless communication with each other, comprising:

• a terminal side authentication parameter acquiring step of acquiring, as an authenticating communication parameter, a communication parameter which is temporarily common during communication with the wireless base station;
• a terminal side authentication key generating step of generating a first authentication key based on the authenticating communication parameter acquired in the terminal side authentication parameter acquiring step, a hash function shared by the server, and authentication information shared by the server;
• and
• a terminal side authentication key sending step of sending the first authentication key generated in the terminal side authentication key generating step via the wireless base station to the server.

A program executed by a computer of a server used in an authentication system in which a terminal and the server make authentication via a wireless base station, the terminal and the wireless base station make wireless communication with each other, comprising:

• a server side receiving step of receiving a first authentication key with an authenticating communication parameter attached thereto from the wireless base station;
• a server side authentication key generating step of generating a second authentication key based on the authenticating communication parameter received in the server side receiving step, authentication information shared by the terminal, and a hash function shared by the terminal;
• and
• a server side authenticating step of authenticating the terminal by determining whether the second authentication key which has been generated in the server side authentication key generating step and the first authentication key which has been received are identical.