Patent ID: 6115601
Filing Date: 2000-09-05
Classification: H04M

Abstract:
A method of paying for a communication service in a mobile communication system comprising at least one mobile communication appliance comprising a secure module for securely storing data; wherein the mobile communication system comprises a credit reload server; and in that the method comprises the steps of:in the secure module: generating a reload request message and authenticating at least part of the reload request message; the reload request message comprising an identification of the secure module and a module transaction number; andin the mobile communication appliance: transmitting the authenticated reload request message to the reload server;in the reload server: receiving and confirming the authentication of the authenticated reload request message; upon a positive confirmation: verifying whether the module transaction number of the received reload request message matches a server transaction number for the identified secure module; and upon a positive verification:determining a new server transaction number for the identified secure module and storing the new server transaction number as the server transaction number for the identified secure module;generating a reload grant message and authenticating at least part of the reload grant message; the reload grant message comprising an indication of a granted number of communication credits and the server transaction number; andtransmitting the secured reload grant message to the mobile communication appliance;in the mobile communication appliance: receiving the authenticated reload grant message; andin the secure module: confirming the authentication of the authenticated reload grant message; and upon a positive confirmation:determining a new module transaction number from the module transaction number;verifying whether the new module transaction number matches the server transaction number; and upon a positive verification, updating a balance of communication credits stored in the secure module according to the granted number of communication credits and storing the new module transaction number as the module transaction number;the method further comprising registering an attempt to fraud upon receiving one of a reload request message having a module transaction number outside a predetermined range of the server transaction number and upon receiving a reload grant message having a server transaction number outside another predetermined range of the module transaction number.