Abstract: The present invention provides an individual authentication method employing an authentication key which is capable of reliably preventing the illegal use of cards by others, and yet does not require special efforts by the card owner to memorize the same. This individual authentication method is capable of determining whether a card user is the true card owner by registering, together with a personal identification number, personal information relating to private data of the card owner in a device managed directly or indirectly by the card-issuing institution at the time of issuance of the card; randomly selecting for each transaction one or more questions from among a plurality of questions based on the personal information and requesting the card user to answer the questions upon using the card; and verifying the answer contents with the contents of the registered personal information for determining whether the card user is the true card owner.

Abstract: A circulation management system according to the present invention comprises a host computer of a bank, circulation medium issuing means incorporated in automatic teller machines of the bank, and terminals installed in each store, so that a user can purchase commodities or receive services at stores which are tied up with a bank using the circulation medium issued by the bank which has a function equivalent to a predetermined amount of money. The circulation medium issuing means and the terminals are connected to the host computer through lines, and when a circulation medium is issued, the circulation medium issuing means issues the circulation medium for the requested amount with assigning identification codes to the circulation medium within the limit of the balance of deposits of the user. The host computer withdraws an amount equivalent to the issued circulation medium from the account of the user and stores the identification code of the issued circulation medium.