Method for supporting cashless payment

The invention concerns a method for supporting cashless payment as well as a payment interworking server, a mobile terminal and a computer program product for a cashless payment system. A mobile subscriber identity stored in the subscriber identification module of the mobile terminal is sent to a payment interworking unit. The payment interworking unit transmits the mobile subscriber identity to an authentication server of a mobile communication system which replies an authentication number and a signed response. The authentication number is sent to the mobile terminal which calculates a signed response and transmits the signed response to the payment interworking server. This server compares the singed responses received from the authentication server and from the mobile terminal and sends a confirmation message to a POS unit or a billing system, if the received signed result is correct.

TECHNICAL FIELD

The present invention relates to a method for supporting cashless payment using a mobile communication system, a payment interworking server for a cashless payment system, a mobile terminal for a cashless payment system and a computer program product for a cahless payment system. The invention is based on a priority application EP 03292800.4 which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Today's cellular radio system, for example a GSM system (GSM=Global System for Mobile Communication), has an authentication server (HLR) which interacts with subscriber identification modules of mobile terminals for granting access to the cellular radio network. This authentication procedure is used by the mobile exchange to decide whether it should establish a bearer connection with a specific mobile terminal.

Further, U.S. Pat. No. 6,169,890 B1 describes a method for carrying out financial transactions using a mobile telephone system. Each subscriber has a service card which is uniquely associated with the subscriber. A connection between the terminal and the mobile telephone network is established. Access to a service provider's system is provided via said connection. The user enters a card identifying number into the terminal. An authentication is performed by this entered card identification number and user-identifying data read from the SIM card of the terminal. Then, a connection between the terminal and the service provider's payment system is established and the amount to be paid, a confirmation of amount and an approving of payment are given to the service provider's payment system.

It is the object of the present invention to improve cashless payment systems.

SUMMARY OF THE INVENTION

The object of the present invention is achieved by a method for supporting cashless payment 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 method comprises the steps of: transmitting a mobile subscriber identity stored in a subscriber identification module of a mobile terminal of a user to a payment interworking unit; transmitting the mobile subscriber identity from the payment interworking unit to the authentication server of the mobile communication system and requesting, by the payment interworking unit, the calculation of an authentication number and an associated signed response for the user identified by the transmitted mobile subscriber identity; transmitting the calculated authentication number and signed response back to the payment interworking unit; transmitting the calculated authentication number to the mobile terminal; calculating, by the subscriber identification module of the mobile terminal, a signed response based on the authentication number and an encryption key stored in the subscriber identification module and transmitting the calculated signed response to the payment interworking unit; and comparing, by the payment interworking unit, the signed results calculated by the subscriber identification module with the signed result received from the authentication server and sending a confirmation message to a POS unit or a billing system, if the received signed result is correct. The object of the present invention is further achieved by a payment interworking server for a cashless payment system using such mobile communication system, wherein the payment interworking server comprises a control unit that 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, requests 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, receives 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 a signed result calculated by the subscriber identification module with the signed result received from the authentication server and sends a confirmation message to a POS unit or a billing system, if the received signed result is correct. The object of the present invention is further achieved by a mobile terminal for a cashless payment system using such mobile communication system, wherein the mobile terminal comprises a control unit that transmits the mobile subscriber identities 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 to a payment interworking unit, receives an authentication number calculated by the authentication server of the mobile communication system on request of the interworking unit, calculates a signed response based on the received authentication number and on 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. The object of the present invention is further achieved by a computer program product for a cashless payment system using such mobile communication system, wherein the computer program product, when executed by a mobile terminal, performs the aforementioned functions of the mobile terminal control unit.

This invention is built up on the idea to have a payment interworking function between the point of sales and the authentication server of the mobile communication system which simulates vis-á vis the authentication server an exchange of the mobile communication network. Such it reuses the authentication and identification processes of the mobile communication system for a cashless payment system.

The present invention increases the efficiency of the cashless payment system. The cahsless payment system does not require for an own authentication and authorization algorithm. Further, it is not necessary to handle specific personal identification numbers (PINs) or transaction numbers (TANs). Already existing powerful mechanisms of a mobile communication system are reused to provide identification and authentication without the requirement to use this mobile communication system and establish a bearer connection via this mobile communication network. The invention provides a secure, cost efficient and userfriendly authentication of the cashless payment system.

Further advantages are achieved by the embodiments of the invention indicated by the dependent claims.

According to a preferred embodiment of the invention, the mobile terminal is connected to a POS unit (POS=Point of Sales) via a short-range interface and at least a part of the communication between the mobile terminal and the payment interworking unit is carried over this POS unit. The short range interface is, for example, a short range radio interface like a bluetooth interface or a infrared interface. This makes it possible to implement an easy to handle and userfriendly payment process: A mobile terminal can remain in the pocket of the user which stands in the neighborhood of the POS terminal. The amount to be paid, the confirmation of the user and/or the approving of payment by the user can be entered in the POS terminal, without any user interaction between the mobile terminal and the user. The exchange of mobile subscriber identity, authentication number and signed response can be automatically executed between the point of sales and the mobile terminal via the short range interface.

Further, it is also possible that the mobile terminal and the POS unit are connected via a long distance communication network an the POS unit is formed by an internet-server which provides an electronic shop.

Some advantages are achieved when carrying the whole communication between the mobile terminal and the payment interworking unit via the POS unit. The POS unit has full control over the data flow which increases the security and efficiency of the system. For example, the POS unit forwards the mobile subscriber identity to the interworking unit solely when the user has confirmed the amount and has approved the payment. This reduces the work load of the payment interaction unit and increases the security of the system.

Further, the method can be easily adapted to different billing systems and seller's needs: It is possible that the POS unit initiates the payment when receiving the confirmation message from the payment interworking unit. Thereby it is possible to combine the method according to the invention with low-price cashing systems. But, it is also possible that the billing system initiates the payment when receiving the confirmation messages from the payment interworking unit and sends a confirmation to the POS unit about this payment. Further advantages are achieved, if this billing system is a billing system of the mobile operator of the mobile communication system. This system charges the user's mobile operators account when receiving the confirmation message from the payment interworking unit.

Further, the security of the system can be increased by encrypting the communication between the mobile terminal and the payment interworking unit. According to a preferred embodiment of the invention, the mobile terminal encrypts the mobile subscriber identity before sending it to the POS unit and the payment interworking unit decrypts the received mobility subscriber identity, when receiving it from the POS unit. Thereby, the mobile subscriber identity is protected against fraudulent issues.

FIG. 1shows a mobile communication system1, a payment interworking server6, a billing system7, a communication network2, a POS unit51, a mobile terminal3and a user4.

The mobile communication system1is formed by a cellular radio network, for example according to the GSM or UMTS standard (GSM=Global System for Mobile Communication; UMTS=Universal Mobile Telecommunications) or IS-95 or CDMA2000 standard. Such systems comprise one or several authentication servers which interact with mobile terminals for granting access to the mobile communication system. Examplary,FIG. 1shows a GSM based mobile communication system1with an authentication server11, which is formed by the so-called home location register of the GSM network (Home Location Register=HRL). Each time a mobile terminal requests communication services from the mobile communication system1, the authentication server11checks the identity of this mobile terminal by executing an authentication process with the subscriber identity module of this mobile terminal. The authentication server11holds for each of the registered subscriber of the mobile communication system1an encryption key and a mobile subscriber identity. Further, each of the subscriber identification modules assigned to a registered user of the mobile communication system1stores a mobile subscriber identity and encryption key. A mobile terminal is identified by its mobile subscriber identity submitted to the authentication server. The authentication server returns a random number, which is encrypted by the subscriber identity module based on the stored encryption key. The authentication server compares this signed response from the subscriber identification module with the signed response calculated based on the encryption key stored in the authentication server. If the signed result is correct, the authentication server grants access to the mobile communication system.

The billing system7is a billing system of the operator of the mobile communication system1, of a bank, credit card institution, or billing agent. This billing system has the possibility to credit or debit the user.

The communication network2provides communication between the POS unit51, the billing system7and the payment interworking server6. The communication network2can be constituted by an IP network which comprises a plurality of different physical interconnected networks using an IP protocol as level three protocol (IP=Internet Protocol). But, it is also possible that the communication network2is a telephone network, for example a PSTN or ISDN network (PSTN=Public Switched Telecommunication Network; ISDN=Integrated Services Digital Network). Further, it is possible that the network2is a mobile network. Further, it is possible that the communication network2is formed by a network providing both kind of services, wherein different kind of services are used for the communication between the POS unit51and the payment interworking server6and between the payment interworking server6and the billing system7.

The POS unit is a till, a point of sales terminal, a vending machine or a ticket machine. The POS unit51comprises input and output means, for example a display, a keypad, a microphone, a loudspeaker, a mousepad and so on. Further, it comprises a communication unit for communicating via the communication network2and a second communication unit for communicating with the mobile terminal3via a short range interface. Such a short range interface is, for example, an infrared or short range radio interface like a bluetooth interface. But, it is also possible that the second communication unit enables a galvanic connection between the mobile terminal3and the POS unit51. Such galvanic connection is provided by a connector or mobile terminal holding device which fits with the data interface of the mobile terminal3.

The amount to be paid is, for example, entered by the shop keeper or casher in the POS unit. The POS unit transmits the amount to be paid via the short range interface to the mobile terminal3. The mobile terminal3displays the amount to be paid, asking the user to confirm the amount and approving the payment. When the user4gives his approval, the mobile terminal3sends the mobile subscriber identity stored in the subscriber identification module of the mobile terminal3via the short range interface to the POS unit51. The POS unit51sends the received mobile subscriber identity and payment data describing the financial transaction via the communication network2to the payment interworking server6. Such payment data contains, for example, the amount to be paid, the kind of billing system which shall be used for the financial transaction and data identifying an account of the shop holder the amount should be transferred to.

Further, it is possible that user4enters his approval in the POS unit51. According to this embodiment, the mobile terminal3can remain in the pocket of the user4who stands in the neighborhood of the POS unit51. The amount to be paid, the confirmation of the user and/or the approving of payment by the user can be entered in the POS unit51, without any user interaction between the mobile terminal3and the user4. The exchange of mobile subscriber identity, authentication number and a signed response can be automatically executed between the point of sales unit51and the mobile terminal3via the short range interface. Preferably, the short range interface is a bluetooth interface and the bluetooth paring mechanism is used for establishing this communication. At the first time the mobile terminal3and the POS unit51has to communicate with each other, the user4enters an authentication code in the POS unit51. This authentication code is already known to the mobile terminal3or, for example, entered in parallel by the user4. In the following, an authorization procedure is executed between the mobile terminal3and the POS unit51by help of this authorization code. If the authorization is positive, the POS unit51and the mobile terminal3accept each other and execute the above-described exchange of data.

Payment interworking server6sends a request to the authentication server11of the mobile communication system1. This request contains the mobile subscriber identity submitted by the POS unit51and requests the calculation of an authentication number and an associated signed response for the user identified by the transmitted mobile subscriber identity. The authentication server11checks whether the mobile subscriber identity is assigned to a registered subscriber of the mobile communication system1. If the check is negative, it sends a corresponding response message to the payment interworking function6which stops the further transaction process and sends a corresponding message back to the POS unit51. If the check is positive, it calculates a random number and encrypts this random number by the key assigned to the subscriber associated with the received mobile subscriber identity. Then, it sends a response to the payment interworking server6. This response contains this random as authentication number and the calculated signed response. The payment interworking server6sends the authentication number via the communication network2to the POS unit51which forwards it to the mobile terminal3. The subscriber identification module of the terminal3calculates a signed response based on the received authentication number and the encryption key stored in the subscriber identification module. Then, the mobile terminal3sends the signed response via the short range interface to the POS unit51which forwards the signed response via the communication network2to the payment interworking server6.

The payment interworking server6compares the received signed result with the signed result received from the authentication server11. If this check is positive, it sends a confirmation message to the billing system7. This confirmation message gives the billing system7the confirmation that the user4, who has approved the payment, is the registered subscriber of the mobile communication system1specified by the mobile subscriber identity. Further, the confirmation message may contain additional data as the aforementioned payment data and a further specification of the user4, for example, submitted by the authentication server11.

Further, the payment interaction server6sends a confirmation to the POS unit51and to the mobile terminal3, the confirmation confirms the successful execution of the financial transaction.

FIG. 2shows the mobile communication system1with the authentication server11, the communication network2, the payment interworking server6, the billing system7, the mobile terminal3and the user4. Further, it shows a POS unit52and a terminal8.

The terminal8makes it possible for the mobile terminal3to communicate with the POS unit52via the communication network2. For example, the terminal8is a computer connected on the one side to the communication network2and providing on the other side a short range interface to the terminal3. Further, it is possible that the terminal8provides a graphical user interface to the user4which is used by the user4to interact with the POS unit52. For example, the terminal8provides a WEB browser for such interaction.

The POS unit52is a internet-server which provides fuctionalities of an electronic store, electronic booking or ticketing system. For arranging and acknowledging a financial transaction, the terminal8and the mobile terminal3at the user side41interacts with the POS unit52. When the user4has confirmed an amount which has to be paid and has approved the payment by entering a corresponding command in the mobile terminal3or the terminal8, the POS unit52performs the same kind of functionalities as already described for the POS unit51according toFIG. 1.

FIG. 3shows a detailed functional view of a system according toFIG. 1.FIG. 3shows the terminal3, the user4, the POS unit51, the payment interworking server6, the authentication server11and the billing system7.

The terminal3is a mobile phone, or a PDA or computer with a mobile communication unit (PDA=Personal Digital Assistant). It comprises several input and output means, a microprocessor with associated peripheral components and program code executed by this microprocessor. The functionalities of the mobile terminal3are performed by the execution of this program code by the microprocessor. From the functional point of view, the terminal3comprises two control units31and33and a subscriber identification module32. The control unit31comprises all basic functionalities of the mobile terminal3which enables the mobile terminal3to communicate via the mobile communication system1. The subscriber identification module32is preferably located on a SIM card which is releasable arranged in the mobile terminal3. The control unit33provides the specific functionalities which are necessary for supporting the method according to this invention. Preferably, the control unit33is constituted by a software packet downloaded via the mobile communication system1to the mobile terminal3. Such software package is, for example, a JAVA-Midlet. Further, it is possible that the software package is preinstalled in the mobile terminal3, or in the SIM card of the mobile terminal3or is downloaded to the mobile terminal3via a data interface of the mobile terminal3, for example, a bluetooth interface.

This software package as such or a computer readable storage medium with this software package stored on it forms a computer program product according to this invention.

The payment interworking server6is formed by one or several interconnected computers, a software platform and application programs executed by these computers. The functionalities of the payment interworking server6are performed by the execution of this software by the hardware platform of this computer or these computers. From the functional point of view, the payment interworking server6provides a communication unit61, a control unit62and a storage unit63. The communication unit61contains all functionalities of the payment interworking server6which enables the payment interworking server6to communicate with the POS terminal51and the authentication server11. Preferably, the communication unit61contains additional functionalities to establish a secure communication via the communication network2and with the authentication server11.

The authentication server11comprises, from the functional point of view, a control unit12and a storage unit13.

If the POS unit51receives from the user4a command which confirms an amount that should be paid, the POS unit sends a request message91via the short range interface to the terminal3. The control unit33handles this request and requests the submission of the mobile subscriber identity from the subscriber identification module32. Then, it sends the determined mobile subscriber identity, preferably in an encoded form, within a response message92to the POS unit51. If the POS unit51receives a further command93from the user4which approves the payment of the amount, it submits the mobile subscriber identity within a message94to the payment interworking server6. The control unit62creates a payment process, sends a request95to the authentication server11and receives a response96containing an authentication number and an associated signed response. The control unit62stores the received signed response within the storage unit63and forwards the authentication number as part of a response97to the POS unit51, which forwards this response to the terminal3.

Further, it is possible that the mobile subscriber identity and/or the authentication number are directly transmitted from the mobile terminal3to the payment interaction server6. Further, it is also possible that the authentication server11directly transmits the authentication number to the terminal3via the mobile communication system1.

The control unit33forwards the received authentication number to the subscriber identification module32and requests the calculation of the associated signed response. If it receives the signed response, it submits the signed response within a message98to the POS unit51which forwards this message to a payment interworking server6. The payment process of the control unit62associated with this transaction compares the received signed response with the associated signed response stored in the storage unit63. If the signed response is correct, it sends a confirmation message99to the POS unit51. Further, the payment process records an associated transaction record containing the relevant data of the authorization, for example, a log file storing the details of the communication with the POS unit and the authentication server11of the mobile communication system1. Further, it assigns a transaction reference number to this record and submits this reference number within the confirmation message99to the POS unit51. This reference number may be lateron used by the shop holder to prove positive authentication by the payment interworking server6.

Preferably, the communication between the mobile terminal3and the POS unit51is a secured communication, which uses, for example, a specific security protocol like a SSL secured protocol layer. Further, the communication between the POS terminal51and the payment interworking server6is based on a secured connection established via the communication network2.

Further, it is possible that the control unit12submits to the payment interworking server6additional information containing data like the credit rating or a maximum transaction amount. Such data is elected by the control unit12from the subscriber data available within the mobile communication system. Further, it is possible that the amount of the transaction is submitted within the message93to the authentication server11, which gives in the message96a response whether this amount is acceptable or not acceptable.

When receiving the confirmation message99, the POS unit51creates the transaction data and submits it to the billing system7. This billing system might be, for example, a bank which performs a bank transfer, for example, on the basis of direct debiting mandate. Further, it is possible that the POS unit collects additional payment data from a bank card or credit card provided by the user4.