Cellular radio data processing implemented by a sim card, in particular for security purposes

0001The present invention relates to radio cellular data processing, implemented by computer means of a SIM card, in particular for monitoring a current location of a terminal receiving this SIM card, for example for security purposes.

0002The terminal may for example be an equipment communicating with a server via a radio-cellular network, such as a payment terminal in a store or a restaurant. For security reasons, it is not desired that a malicious user can steal the terminal for hacking or other purposes.

0003To this end, a remote server (for example a control server) tracks the location of the terminal as a function of radio frequency cell identifiers in which the terminal is located. The terminal's SIM card usually manages the transmission to this server of cell change notifications.

0004Thus, the SIM card of a terminal in a mobility situation usually receives from the network a current cell identifier (for example at regular times, or during the establishment of a call), and transmits these cell identifiers to a server which checks, using this data, that the terminal does not move beyond a certain distance from a predetermined position.

0005However, the reception and processing of all notifications by the server, each time the cell identifier is received, ultimately generates a large workload with the server.

0006To limit this problem, we could provide that the SIM card:<ul id="ul0001" list-style="dash"><li>compare the current cell identifier with an identifier previously stored in memory (typically the cell identifier indicated by the network at the previous instant, or during the previous communication),</li><li>then generates a notification intended for the remote server, only in the event of a difference between the current identifier and the cell identifier previously stored in memory.</li></ul>

0007However, here again, in certain situations where for example the payment terminal is in a large restaurant or a department store, covered by several cells at the same time, the mobile payment terminal can generate a multiplicity of notifications from the SIM card. to the server each time the cell is changed.

0008Such notifications would then limit the speed of processing of the SIM card, and the payment terminal would present unnecessary delays. The server itself must still process all the notifications it receives while these terminal locations are usual and very close to its presumed original location.

0009The document <patcit id="pcit0001" dnum="US2012172082A1"><text>US 2012/172082 A1</text></patcit> discloses the management of a cell list within a terminal with the aim of minimizing notifications between the terminal and the network by only signaling certain cell changes.

0010The present invention improves the situation.

0011The invention is defined in the claims.

0012To this end, it proposes a method for processing radio-cellular data, implemented by computer means including a SIM card, in which the SIM card of a terminal in a mobility situation:<ul id="ul0002" list-style="dash"><li>receives a current cell identifier,</li><li>compare the current identifier with an identifier previously stored in memory,</li></ul>the SIM card being capable of generating a notification intended for a remote server, in the event of a difference between the current identifier and an identifier previously stored in memory.

0013In particular, the SIM card stores in memory a list of current identifiers of respective cells in which the terminal is successively located, and the transmission of a notification to the server is conditioned by the absence of the current identifier in this list. .

0014Thus, the SIM card of the invention maintains a white list of cells in which the terminal has been able to go (for example cells adjacent to a predetermined origin location). As long as the terminal goes, in a mobile situation, in one of these known cells, the SIM card does not send a notification to the server and does not overload with its resources, those of the terminal and those of the server.

0015Thus, in a particular embodiment, the SIM card performs the following steps, after reception of a current cell identifier:<ol id="ol0001"><li>a) determine if the current cell identifier is in said list, and if the current cell identifier is not in the list:</li><li>b) issue a cell change notification to the server, and</li><li>c) store the current cell identifier in the list.</li></ol>

0016Of course, in step a), if the current cell identifier is in the aforementioned list, the SIM card does not carry out cell change notification to the server.

0017It should be noted that the above terms “SIM card” are commonly used to designate a “UICC” card (for “Universal Integrated Circuit Card” as defined by the ETSI organization) comprising at least one of the SIM applications , USIM, ISIM and HPSIM (defined by the 3GPP standard). It will thus be understood that the terms “SIM card” here designate such a UICC card.

0018Advantageously, the implementation of the present invention in no way alters the security of the verification of the location of the terminal.

0019For example, in one embodiment, a notification sent by the SIM card to the server includes the current cell identifier, allowing the server to compare a current location of the terminal, corresponding to the current cell identifier, to a predetermined location (typically an original location, presumed), and to execute an alert routine if the current location does not verify, relative to the predetermined location, a chosen criterion.

0020For example, the server can execute the aforementioned alert routine if the current location and the predetermined location are deviated by a distance greater than a chosen threshold distance.

0021In one embodiment, on receipt of an alert message from the server, the SIM card inhibits any transmission of cell change notification to the server. Thus, the SIM card no longer emits any notification to the server of cell change, which again makes it possible not to overload the server with processing of unnecessary notifications.

0022In one embodiment, the SIM card receives an order from the server to initiate the execution of the steps of the method, for example after a first commissioning of the SIM card. In this case, the server can retrieve the first cell identifier notified to it by the SIM card and thus predetermine that it is the above-mentioned original location.

0023As indicated above, the invention finds an advantageous application in the case of a terminal corresponding to an item of equipment such as a payment terminal, or else a rented item of equipment which must not leave a predefined area (for example item of equipment site), the SIM card then implementing a secure process within the framework of a machine-to-machine application. Thus, in one embodiment, the terminal is intended to communicate with the remote server, in machine to machine mode.

0024The present invention also relates to a SIM card comprising means including a memory programmed to execute the steps of the above method.

0025The present invention also relates to a computer program comprising instructions for implementing the above method when this program is executed by a processor.

0026Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings in which:<ul id="ul0003" list-style="dash"><li>the <figref idref="f0001">figure 1</figref> illustrates the material elements involved in the implementation of the method, according to an exemplary embodiment,</li><li>the <figref idref="f0001">figure 2a</figref> illustrates a situation of mobility of a terminal comprising a SIM card according to the invention,</li><li>the <figref idref="f0002">figure 2b</figref> illustrates the steps of a method within the meaning of the invention according to an exemplary embodiment.</li></ul>

0027With reference to the <figref idref="f0001">figure 1</figref>, the SIM card typically comprises a microcontroller (including for example a PROC processor) and a memory unit MEM with for example:<ul id="ul0004" list-style="dash"><li>a working RAM to store, for example, a common cell C cell identifier,</li><li>non-volatile memory to store:<ul id="ul0005" list-style="none"><li>* computer program instructions, the execution of which makes it possible to implement the above process, and</li><li>* the above-mentioned list of cell identifiers previously notified to the server.</li></ul></li></ul>

0028The SIM card also includes an INT connection interface with the TER terminal which receives it. In service, the SIM card can communicate via the RES network with a SER control server, to which the SIM card notifies the successive changes of cells whose identifiers are not in the list. It will be understood that this computer program can typically have an algorithm whose flowchart can be represented by the<figref idref="f0002">figure 2b</figref> commented below.

0029With reference to the <figref idref="f0002">figure 2b</figref>, the method begins with a first step S1, during which, for example, the SIM card sends an initial identifier Cell 0 of the cell in which the SIM card is put into service for the first time in the terminal TER. This Cell 0 identifier is stored in the memory of the SIM card in a white list of cell identifiers in which the TER terminal is located successively.

0030Then, when the terminal is in a mobility situation towards a current cell, with the current identifier Cell C, as illustrated in the <figref idref="f0001">figure 2a</figref>, in step S2, the SIM card retrieves this current identifier Cell C. The SIM card checks in step S3 if this current identifier Cell C already belongs to a list of cell identifiers stored by the SIM card and which correspond to all successive cells with which the terminal has been linked (since the SIM card was put into service in this terminal).

0031If the current cell C cell identifier already belongs to this list (arrow OK at the end of the S3 test), the SIM card does not send a notification to the SER server and returns to a mode of waiting for a possible new mobility situation.

0032On the other hand, if the current cell C cell identifier does not belong to this list (arrow KO at the end of the S3 test), the SIM card sends a notification to the SER server which includes the current cell C cell identifier, at step S4 and updates in step S5 the list which it stores by adding thereto the current identifier of cell Cell C. Then, the SIM card returns to a mode of waiting for a possible new situation mobility.

0033In the example described here, the method can continue with the server SER which, on receipt of the notification comprising the current cell identifier Cell C, determines in step S6 a current location loc C, corresponding to this current identifier Cell C cell. For this purpose, the SER server can have recourse to a database DB of locations according to cell identifiers.

0034Then, in the test S7, the server SER determines whether the current location loc C is distant from the location loc 0 of commissioning of the SIM card (corresponding to the initial identifier Cell 0) by more than a threshold distance THR, chosen. This situation corresponds to the case, for example, where the TER terminal moves away outside the boundaries of the store or restaurant (or even the construction site) in which it is usually used. If this is the case (arrow KO at the end of the S7 test), the SER server can generate an alarm in step S8 and optionally send an order to the SIM card in step S9 so that it goes into a state blocked (in which typically it no longer sends a notification to the server, and possibly it no longer allows the terminal to connect to the network).

0035On the other hand, as long as the distance between the current location loc C and the initial location loc 0 remains below the THR threshold (arrow OK at the end of the S7 test), the SER server does not generate an alarm and returns to a situation of waiting for a possible notification in case of mobility in a new cell.

0036So, in summary:<ul id="ul0006" list-style="dash" compact="compact"><li>at startup, the SIM card sends the initial identifier (Cell 0) of the cell to which it is connected (and of course adds this initial identifier Cell 0 to the white list which it stores in memory),</li><li>the SIM card then monitors the successive identifiers of cells to which it connects, as follows:<ul id="ul0007" list-style="none" compact="compact"><li>∘ detection of a cell change, of current identifier Cell C,</li><li>∘ verification of the membership of the current Cell C identifier in the white list stored on the SIM card,</li><li>∘ if the current Cell C identifier belongs to the white list, the SIM card ends its operations and returns to a standby mode, in order to avoid sending a multiplicity of notifications,</li><li>∘ if the current Cell C identifier does not belong to the whitelist, then:<ul id="ul0008" list-style="none" compact="compact"><li>▪ the list is updated in the memory MEM of the SIM card by adding thereto the current identifier Cell C, and</li><li>▪ the SIM card sends the SER server a notification including the current Cell C identifier,</li></ul></li></ul></li><li>the SER server interrogates a database DB (of “location server” type) to translate the current identifier Cell C received into geographic data (typically a current location loc C to be compared with an origin location loc 0 corresponding to the initial cell identifier Cell 0),</li><li>depending on the distance between the current location loc C and the original location loc 0, the SER server triggers an alert or not.</li></ul>

0037Notifications from the SIM card to the SER server are for example in the form of an SMS message addressed to the server (or of the “USSD” type (for “Unstructured Supplementary Service Data”), or “BIP” (for “Independent Protocol Bearer”). , or https, or others).

0038The advantage of doing so within the meaning of the invention is then to limit the number of notifications sent (thus avoiding the cost of an SMS notification, by offering bandwidth savings, but also energy savings on the equipment carrying the SIM card).

0039The invention then makes it possible to offer an effective service in the field of geolocation, more precisely that of the alert in the event of displacement (service of the so-called “GPS anchor alarm” type), while limiting the notifications sent by the SIM card to the SER server.

0040This type of service is generally based on GPS / Glonass type solutions, which makes it possible to dispense with a GPS type device (and therefore deploy the service on equipment not equipped with a GPS chip). In addition, the coverage of a cellular network (of GSM or UMTS type) is very often of better quality than that of a satellite in the GPS application in urban environment (particularly indoors).

0041Of course, the present invention is not limited to the embodiments described above by way of example; it extends to other variants.

0042For example, the possibility of starting the monitoring of a cell change from the commissioning of the SIM card in the TER terminal has been described above. However, in a variant, monitoring can start on the order of the SER server after this commissioning.

0043Furthermore, an embodiment has been described above in which the current location is compared to an initial location (with an authorized distance between the two locations). However, in other possible embodiments, it is possible to trigger an alarm in the event that the cell identifier simply corresponds to an unauthorized cell (for example predetermined and at the periphery of a particular zone).

0044In addition, in the embodiment described above, the radio cellular data processing method according to the invention is implemented by computer means including a UICC card (commonly known as a SIM card). However, according to other embodiments, the invention can be implemented by a software module, distinct from a UICC card, and realizing or emulating all or part of the functionalities of a UICC card.

0045Consequently, in general, the method according to the invention is implemented by a hardware and / or software module, designated here by “security module”, and according to the embodiment chosen, such a security module may include a UICC card, or may be distinct from a UICC card and, in the latter case, this module can then be configured to implement all or part of the functionalities provided by a UICC card.