Abstract:
Physically access-protected service access, such as a service flap having a mechanical lock, for example, are used to ensure the secure establishment of security check information. Logical access security to service functions is produced using the security check information via additional, decentralized service interfaces. For this purpose, it is not the mobile service device that is connected to the physically access-protected communications interface, but rather a second authentication module associated with the mobile service device. Security check information is provided by the authentication module for secure service access to the network via additional, decentralized communications interfaces of the network.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a method, a system and an authentication module for dynamically authorizing a mobile communications device for a network. In particular, these are understood to be mobile service devices, which are permitted access to networks of systems to be serviced. 
     Technical facilities require servicing work at regular intervals or if they are functioning incorrectly. Mobile service devices, such as Notebooks or PDAs (Personal Digital Assistant) are usually used here, which obtain service access to a specific industrial device, such as for instance a train, a signal box, a production control or a medical device by way of a decentralized accessible interface. The connection to the decentralized accessible interface is established wirelessly or by wire. By way of the service access, diagnostic functions can be called up, fault memories read out, configuration settings of the industrial system modified or software updates imported. 
     In order to prevent misuse of these sensitive communications interfaces, it must be ensured that service access is only permitted to authorized mobile service devices. 
     To grant access rights, an authentication check is therefore usually performed, in which the proof of a claimed identity and thus the authorization for access to the respective service interface is checked. If the authentication check is successful, the previously allocated access rights are granted to the respective user. 
     Most known authentication methods are based on the entity to be authenticated having to prove to a checking entity that it is in possession of a secret and/or an object. The best-known authentication method is the transmission of a password, in which the authenticating entity transmits a secret password directly to a checking entity. The checking entity or the authentication checking unit then checks the accuracy of the transmitted password. 
     A further known possibility for preventing the misuse of service accesses is to provide the respective network connector for service access in a physically access-protected area. For instance, the network connector can be secured with a closeable service flap or can be located in a closeable room. Such a procedure requires a large number of service interfaces, above all in spatially distributed systems. 
     When monitoring service accesses in large systems, such methods therefore involve a significant administrative effort, which arises for instance through the issuing of passwords or mechanical keys. The mechanical closure of communications interfaces is also only possible in the case of wired accesses, while with wireless accesses, such a method cannot be used. With wireless service accesses, there is therefore only the option of protecting the respective communications interfaces by specifying service passwords. Particularly with the temporary use of service technicians or freelancers, the respective service passwords should be changed again after terminating the service task on the system to be serviced, which in turn results in an increased configurative outlay in terms of using this method. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is accordingly to create a method for authorizing network accesses, which reduces the administration and configuration outlay in comparison with previously known methods. This object is achieved by a method, a system and an authentication module having the features of the claims. Advantageous developments of the invention are specified in the dependent claims. 
     In the inventive method for dynamically authorizing a mobile communications device for a network, an authentication module associated with the mobile communications device is connected to the network by way of a physically access-protected communications interface. The mobile communications device conveys an access request to the network by way of a further wireless or wired communications interface. An item of security check information of the mobile communications device is provided to an authentication checking unit of the network by the authentication module. The authentication checking unit authorizes the mobile communications device for the network with the aid of the access request and the security check information. 
     An underlying aspect of the present invention is to use a physically access-protected service access, such as for instance an opening for service with a mechanical lock, in order to safeguard the secure facility of the security check information required for the logical access security in terms of at least one service function via at least one further decentralized service interface. For this purpose, it is not the mobile service device that is connected to the physically access-protected communications interface, but rather a second authentication module associated with the mobile service device. Security check information is provided by means of said authentication module for secure service access to the network via additional, decentralized communications interfaces of the network. The access can herewith take place directly with the network and/or with a component of the network, for instance a control computer. 
     In a further development of the present invention, the security check information is configuration data for setting up a secure network connection of the mobile communications device. This configuration data includes for instance identification information of the mobile communications device, such as for instance a serial number, a network address of the network adapter or a key associated with the mobile communications device. Once the identity of the mobile communications device has been made known to the network in this way by the authentication module, access to the further communications interfaces of the network is hereinafter granted to the mobile communications device following notification of its identity. The mobile communications device therefore uses the security configuration data for authentication with the network, which was already provided to the network by means of the authentication module. The network herewith checks the security configuration data provided by the authentication module and the security configuration data transferred by the mobile communications device. 
     In a development of the present invention, the security check information is an authentication functionality for setting up a secure network connection of the mobile communications device. A check command is herewith transferred to the authentication module by the authentication check unit. A check response is determined by the authentication module with the aid of the check command and the check response is transferred to the authentication check unit by means of the authentication module. The check response is finally checked by the authentication check unit. 
     In this development of the present invention, it is not only security configuration data that is provided by the authentication module but instead the authentication module takes over the authentication relative to the network in a challenge-response method for the mobile communications device. From the mobile communications device&#39;s point of view, the network in this case operates as an authentication proxy and the authentication module operates as an authentication server. The challenge-response method for the authentication check may be based here on symmetrical or asymmetrical cryptography. 
     The inventive system for dynamic authorization of a mobile communications device for a network by an authentication check unit of the network comprises an authentication module associated with the mobile communications device, which can be connected to the network via a physically access-protected communications interface. The mobile communications device itself can be connected to the network via further wireless or wired communications interfaces. The authentication module comprises means for providing security check information of the mobile communications device, with the aid of which the mobile communications device is authorized by the authentication check unit of the network. The inventive authentication module is set up to implement the inventive method. 
     The invention is explained in more detail below with exemplary embodiments with the aid of the appended figures, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  shows a schematic representation of an inventive system for dynamic authorization of service accesses in the example of a train carriage, 
         FIG. 2  shows a schematic representation of a flowchart of the inventive method for dynamic authorization of service accesses. 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first and a second train carriage  101 ,  102 , the control devices of which are shown schematically in each instance. A train control system  103 , a passenger infotainment system  104  and a train service system  105  are shown, which are connected to one another by way of a network. The network of the individual train carriage  101 ,  102  is coupled to one another via electro couplings  106 . Gateways  107 ,  108  are also shown, by way of which the network communication is routed between the individual train carriages. There can be wireless of wired external access to the network. The figure shows a wireless access  109  as a wireless LAN Access Point and a wired access  110 . 
     To now enable a mobile service device  111  to access the wireless access point and therefore access the service network of the train, an authentication module  112  associated with the mobile service device is used in a service access  110 . The service access  110  is attached behind a closeable service flap so that this is only accessible with the aid of the suitable mechanical key. 
     A decentralized service access to individual control devices is authorized in this way, with which the mobile service device  111  is connected wirelessly via the access point  109  or with which it is directly connected via a cable link (not shown). 
     In addition, the mobile service device can obtain access to service functions of a connected train part  102 . The authentication module  112  need not be unplugged and plugged into the other train carriages to do this. The method can therefore also be used if the further train carriage does not have its own service access for the authentication module  112 . It is sufficient if such a service access is only provided in one train carriage. 
     Possible technical realizations for dynamic authorization of a mobile communications device with the aid of an authentication module are described below for a network. 
     Since the authentication module  112  associated with the mobile communications device  111  is connected to the network via a physical access-protected communications interface  110 , the mobile communications device  111  conveys an access request to the network via a further wireless communications interface  109 . The authentication check unit of the network (not shown) thereupon checks a predeterminable network access (here  110 ) for the presence of a connected authentication module  112 . 
     In this embodiment of the present invention, the authentication check unit of the network checks, after receiving an access request from a mobile communications device, a predeterminable network access (Port XY) for the presence of a connected authentication module. In an alternative embodiment, the authentication check unit of the network regularly checks for instance a predeterminable network access (Port XY) as to whether an authentication module was connected there. In a further embodiment the authentication check unit of the network checks several predeterminable network accesses for the presence of a connected authentication module. 
     The claimed authentication module  112  then provides security check information of the mobile communications device to the authentication check unit of the network. 
     In an embodiment of the present invention, the security check information is configuration data for setting up a secure network connection of the mobile communications device. This configuration data includes for instance identification information of the mobile communications device, such as a serial number, a network address of the network adapter or a key associated with the mobile communications device. 
     In an alternative embodiment of the present invention, the security check information is an authentication functionality for setting up a secure network connection of the mobile communications device. In this embodiment a check command is conveyed to the authentication module  112  by the authentication check unit. A check response is determined by the authentication module  112  with the aid of the check command and the check response is conveyed to the authentication check unit by the authentication module  112 . The check response is finally checked by the authentication check unit. 
     In this embodiment of the present invention, it is not only security configuration data which is provided by the authentication module  112  but instead the authentication module takes over the authentication relative to the network in a challenge-response method for the mobile communications device  111 . From the mobile communications device&#39;s point of view, the network operates in this case as an authentication proxy and the authentication module  112  as an authentication server. The challenge-response method for authenticity checking can be based here on symmetrical or asymmetrical cryptography. It can be realized for instance by means of an EAP protocol (Extensible Authentication Protocol) or according to a 4-way handshake in accordance with IEEE 802.11. 
     The authentication check unit finally authorizes the mobile communications device  111  for the network with the aid of the access request and the security check information. 
     Since the identity of the mobile communications device was made known to the network by the authentication module, access to the further communications interfaces of the network is hereinafter granted to the mobile communications device after communicating its identity. 
     In an embodiment of the present invention, a granted service access remains valid provided the authentication module is inserted. In a further embodiment of the present invention, a granted service access remains valid for a predeterminable period of time, irrespective of whether or not the authentication module is inserted. 
     Provided service access is granted to a mobile communications device, it can repeatedly be given service access. Therefore after interrupting a connection or in the event of a change to another communications interface in the network, access can be granted to the network. 
     An already existing service access of a mobile communications device can be terminated if the service access granted to the mobile communications device is no longer valid, e.g. if the authorization module associated with the mobile communications device is separated from the network. In a variant, an already existing service access also remains, even if the service access granted to the mobile communications device is no longer valid. It can then however not obtain service access again, e.g. at another communications interface of the network. 
     In an embodiment of the present invention, a warning message is generated if a connection between the mobile service device and the authentication module had not existed for a certain period of time or the authorization was not deactivated again. 
     In a further variant, deactivation of the access authorization takes place if the access was not used during a predeterminable period of time. 
     In an embodiment of the present invention, a mobile service device is associated with a specific authentication module. In a variant, the changeable bond of the authentication module to a specific mobile service device takes place by it being connected to the mobile service device. 
     The described method temporarily authorizes a mobile service device which can be associated with the authentication module for service access to a specific industrial system. The thus authorized mobile service device may access further, in particular wireless service interfaces of the industrial system. Here it uses for instance security configuration data for authentication relative to the industrial system, which is checked by the industrial system using the security configuration data set up by means of the authentication module. 
     A temporary bond is set up, wherein a physical access protection is used as a security feature. This temporary bond enables the protected service access to this industrial system by means of this bound mobile service device, wherein further interfaces can be used herefor, which were not used by the access protection used to set up the bond. The physical access protection is therefore used to set up a logical access protection which is independent thereof. 
       FIG. 2  shows in a schematic representation a flowchart of the inventive method for dynamic authorization of a network access. The service flap of an industrial system is first opened  201 . The authentication module is then inserted. The mobile service device is then connected to a service interface wirelessly or by wire. A check is hereinafter carried out to determine whether the inserted authentication module is associated with the mobile service device and has a service authorization  204 . If this is not the case, the service access is blocked  205 . If the inserted authentication module can be associated with the mobile service device and the mobile service device has a service authorization, the service access is granted  206  and the service task can be implemented  207 . Finally, the service device is separated from the service interface  208 . The authentication module can hereinafter likewise be removed  209 . Finally the service flap is closed again mechanically  210 . 
     The basic idea behind the invention can also be transferred to other mobile communications devices, such as for instance the telephone of a train conductor or the device for checking tickets, which are dynamically linked to the respective network. 
     An existing physical access security is used in order to set up a logical access security to service functions, which are not covered by the physical access security. The administrative outlay for managing logical security information is therefore reduced or avoided. 
     Service access is not, as currently usual, only possible by way of the physically protected service access, but the service device can be carried along decentrally, in order also to be able to access the industrial system spatially more independently, for instance by way of WLAN. Particularly with a train equipped with WLAN, the authentication module must only be inserted behind the service flap in order thereupon to be able to access train service functions in the entire train via WLAN. An option which is extremely simple to use is thus created, in order to permit a specific mobile service device access to service functions.