To provide an electronic commerce system for safely and smoothly carrying out only authentic commercial transaction by preventing a malicious member store side from performing imaginary commercial transaction by using a unique number acquired in the past.
The electronic commerce system is provided with a member terminal owning an IC card in which a unique number associated with a credit number is recorded, a member store terminal capable of performing commercial transaction settlement by the IC card, a unique number acquiring server for acquiring the unique number of the IC card from the member terminal, and for adding a specific message authentication code valid only for the commercial transaction to the unique number, and for transmitting it to the member store terminal and a credit inquiry accepting server, the credit inquiry accepting server for managing the transmitted unique number and specific message authentication code by associating them, and for accepting a credit inquiry request from the member store terminal by determining the validity of the specific message authentication code and an issue company server for executing credit inquiry processing based on the unique number.
KAWASHIMA TAKU
IMAI KAZUO
HAYAASHI HIROSHI
Tetsuo Kanamoto
Koji Hagiwara