Electronic purse and payment protocol for making secure payments in different currencies, comprises storage of certificated conversion table and comparison of electronic signatures

摘要

A terminal using a particular currency receives a conversion table from a bank which is authenticated by a key (K). When a card using a different currency is entered the terminal supplies a rate and an electronic signature (Sk) which is compared to an electronic signature (Skc) produced by the card. if the two signatures are the same the transaction may proceed subject to further checks on presentation and transaction dates