Patent ID: 8533472

Claim:
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) wherein the temporary ID is calculated at the server and the terminal by further hashing the value S(k, i), which has been hashed, with a second hash function J that is shared between the server and the terminal and wherein the server notifies the terminal of the fact that the number of times of hashing operations has been changed after changing the number of times of hashing operations at the server and wherein in case the server makes communication with the terminal, a temporary ID before changing and a temporary ID after the changing which are held in the server are used in succession so as to request the terminal to send a signal to the server; or (B) wherein at each of the server and the terminal, preprocessing related to the number of times of hashing operations i is carried out before hashing i times with the first hash function H, and a value obtained by the preprocessing and hashing with the first hash function H is calculated as the temporary ID, wherein the server notifies the terminal of the fact that the number of times of hashing operations has been changed after changing the number of times of hashing operations at the server and wherein in case the server makes communication with the terminal, a temporary ID before changing and a temporary ID after the changing which are held in the server are used in succession so as to request the terminal to send a signal to the server.