Authentication method, authentication system, payment system, user apparatus and recording medium containing program for conducting authentication

摘要

The above-described objects of the present invention are achieved by, in an authentication system for authenticating users who are parties to a transaction, an authentication method includes the steps of (a) supplying a first user with a matching key for a prospective transaction, (b) receiving at a second user the matching key supplied to the first user; and (c) matching the key supplied from the first user to the second user against the key supplied to the first user, after the second user has received the key from the first user.