The Internet Open Trading Protocol (IOTP) provides an interoperable framework for Internet commerce. It is payment system independent and encapsulates payment systems such as SET, Secure Channel Credit/Debit, Mondex, CyberCoin, GeldKarte, etc. IOTP is able to handle cases where such merchant roles as the shopping site, the Payment Handler, the Delivery Handler of goods or services, and the provider of customer support are performed by different parties or by one party.