Shopping system

摘要

A shopping system for safely communicating shopping data among information processors has first to third information processors (1, 2, 3). The first information processor (1) has a first storage unit (13) for storing an address to which ordering data is to be transmitted and a second storage unit (11) for storing electronic money and transmits ordering data in accordance with an order. The second information processor (2) responds to the ordering data to issue a payment address and invoice data (51) obtained by digitally signing an invoice. The first information processor responds to the invoice data to transmit an amount of electronic money corresponding to the order to the payment address. The third information processor (3) responds to reception of the electronic money to issue a receipt (53) digitally signed by a private key. The first information processor transmits the digitally signed receipt received from the third information processor to the second information processor. The first information processor can digitally sign the invoice data digitally signed by the second information processor to transmit it to the third information processor. The third information processor checks two signatures on the received invoice data of one is signed by the second information processor and the other is signed by the first information processor. The first information processor transmits a request for repaying the electronic money transmitted to the third information processor in accordance with the order to the second information processor, the second information processor transmits repayment permit data including data for specifying a repaying apparatus, an amount of refund and data for specifying a refund receiving apparatus after digitally signing the repayment permit data by a private key, and the first information processor responds to the electronic money remitted in accordance with the repayment request to transmit a repayment receipt obtained by digitally signing data including identification of the repayment permit data by a private key from the second information processor to the third information processor.