Abstract: In a system for conducting transactions with a multifunctional card having an integrated circuit, the circuit contains a bank application associated with the user's account-keeping bank and at least one purse application associated with a services supplier or manufacturer. With the aid of an apparatus communicating with the card, the card user can load a selectable sum of money into the purse application. The purse supplier is provided with a transaction certificate about the sum loaded in the purse and to be credited to the purse supplier's account, without a need for storing the secret data necessary for preparing this certificate in the purse application or in the purse terminal.