Abstract: The invention relates to a method for restricting the access to data of group members of a service subscriber group. Group members of a service subscriber group are each assigned an identifier. The data of the group members are assigned to the identifier in each case and the data of the group members are stored in a data memory (DS2) of a group management computer (GR) which manages the service subscriber group. Applying the method, a first group member requests a service, providing the identifier of a second group member, the performance of said service requiring the data of the second group member. The identifier of the second group member is sent to the group management computer, which verifies whether the requested service using the data of the second group member is authorized, and in the case where an authorization exists the data of the second group member are sent to a service computer (DR1) controlling the performance of the requested service.

Abstract: A method transmits data relating to a payment operation from a mobile communication terminal (KEG) to a payment system (ZS1, ZS2) in a communication network (GPRS). A server (S) in the communication network uses a first communication protocol (OTA) to receive payment data which come from an application program (A) running on the communication terminal. The server recognizes the communication terminal and the application program (A). The server uses a second communication protocol to transmit the payment data to the payment system (ZS2). In addition, the server transmits terminal data identifying the communication terminal to the payment system, which informs the payment system about the payment debtor. The server also transmits program data identifying the application program to the payment system, which informs the payment system about the payment receiver.

Abstract: Method for paying an amount electronically, in particular a relatively large amount or a series of very small amounts for use of an application made available by a service provider in a data network, in particular the Internet, by a customer to a trader by involving a payment system server of a payment system provider, the payment being carried out by transmitting a confirmation message from a customer terminal via a mobile telephone network using USSD.