Method for supporting cashless payment

A payment interworking server for a cashless payment system using a mobile communication system, wherein the mobile communication system comprises an authentication server which interacts with subscriber identification modules of mobile terminals for granting access to the mobile communication system, the payment interworking server comprises a control unit which:

• transmits a subscriber identity stored in the subscriber identification module of a mobile terminal of a user to the authentication server of the mobile communication system and requesting the calculation of an authentication number and associated signed response for the user identified by the transmitted mobile subscriber identity;
• receives the calculated authentication number and signed response from the authentication server of the mobile communication system;
• transmits the calculated authentication number to the mobile terminal or a POS unit which forwards the calculated authentication number to the mobile terminal;
• receiving a signed response calculated by the subscriber identification module of the mobile terminal based on the authentication number and an encryption key stored in the subscriber identification module;
• and
• compares the signed response calculated by the subscriber identification module with the signed response received from the authentication server and sending a confirmation message to a POS unit or a billing system, if the received signed response is correct.

A mobile terminal for a cashless payment system using a mobile communication system, wherein the mobile communication system comprises an authentication server which interacts with subscriber identification modules of mobile terminals for granting access to the mobile communication system, the mobile terminal comprises a control unit which:

• transmits the mobile subscriber identity stored in the subscriber identification module of the mobile terminal of a user to a payment interworking unit or to a POS unit for forwarding it to a payment interworking unit;
• receives, an authentication number calculated by the authentication server of the mobile communication system on request of the payment interworking unit;
• calculates, a signed response based on the received authentication number and an encryption key stored in the subscriber identification module;
• and
• transmits the calculated signed response to the payment interworking unit or to a POS unit which forwards the calculated signed response to the payment interworking unit,
• wherein the payment interworking unit compares the calculated signed response with another signed response received from the authentication server and sends a confirmation message to the POS unit or a billing system, if the another signed response is correct.

A computer program product for a cashless payment system using a mobile communication system, wherein the mobile communication system comprises an authentication server which interacts with subscriber identification modules of mobile terminals for granting access to the mobile communication system, the computer program product, when executed by a mobile terminal, performs the steps of:

• transmitting the mobile subscriber identity stored in the subscriber identification module of the mobile terminal of a user to a payment interworking unit or to a POS unit for forwarding it to the payment interworking unit;
• receiving, at the payment interworking unit, an authentication number and an associated signed response calculated by the authentication server of the mobile communication system on request of the payment interworking unit;
• initiating the calculation of a signed response, by the mobile terminal, based on the received authentication number and an encryption key stored in the subscriber identification module;
• transmitting the calculated signed response to the payment interworking unit or to a POS unit which forwards the calculated signed response to the payment interworking unit;
• and
• comparing, by the payment interworking unit, the signed response calculated by the mobile terminal with the associated signed response calculated by the authentication server and sending a confirmation message to the POS unit or a billing system, if the associated signed response is correct.