Personal authentication method

Abstract

A user i calculates authentication application information involving a random-number parameter and transmits it to a sales company A. At the sales company A, the received authentication application information is one-way transformed using a random-number parameter and is transmitted to the user i as authentication challenged information. At the user i, an identification number for credit membership of the user and a password are inputted and the received authentication challenge information is transformed using the password to create authentication response information. Then the identification number of the user i and the authentication response information are transmitted to the sales company A. At the sales company A, the received authentication response information is one-way transformed so that the random-number parameter is cancelled so as to produce authentication reference information. Then the received identification number and the authentication reference information are transmitted to the credit company b. At the credit company b, transformed secret information which is stored in advance is retrieved using the received identification number as a key and it is determined whether the transformed secret information and the authentication reference information are equal. If they are equal, the credit company b transmits to the sales company A authentication information indicating correctness of the user i, and if they are not equal, it transmits authentication information indicating that the user i can not be authenticated as a correct user. At the sales company A, the authentication information transmitted from the credit company b is transmitted to the user i.