SMART METER GATEWAY AND METHOD FOR OPERATING A SMART METER GATEWAY

Description

[0001] Smart Meter Gateways (SMGWs) are the central components of smart metering systems. They receive measurement data from meters, store it, and prepare it for market participants. Accordingly, they serve as the central communication unit for smart metering systems, facilitating communication between the various stakeholders. with the Local Metrological Network (LMN) with consumption metering points of one or more consumers, with the Home Area Network (HAN) of the end consumer, in particular with controllable energy consumers or energy producers, and with the Wide Area Network (WAN), in particular with the SMGW administrator and external market participants is being processed.

[0002] Smart meter gateways are subject to strict security guidelines. Compliance with these guidelines must be demonstrated in a certification process conducted by the German Federal Office for Information Security (BSI). All security-critical elements subject to certification are summarized in the so-called "Target of Evaluation" (TOE). This TOE is defined by the Protection Profile (PP) for SMGWs.

[0003] According to the current state of the art, network communication is usually implemented via mobile communication modules outside the TOE.

[0004] Further prior art is the European patent application EP2812837B1.

[0005] One problem arises from the fact that, for the operational use of smart meter gateways (SMGWs), the (large) metering point operators need the ability to monitor the SMGW's operation and, if necessary, correct configurations and parameters that are crucial for its operation. Examples of such situations include monitoring LTE signal quality or changing the metering APN when the metering operation of gateways is to be moved to a different subnet. The necessary functions for this are summarized below under the term "network management (NwMgmt) functions."

[0006] This is usually done for security and organizational reasons in completely separate departments, which have nothing to do with the actual power grid monitoring and do not have official Gateway Administrator (GWA) rights.

[0007] To implement such network management (NwMgmt) functions, it is known to use separate communication modules which, with their own operating system - typically an embedded Linux system - connect the modem of the mobile communication module with the functionality of a router and network management, so that the communication module can forward data relating to network management functions and data relating to communication with the gateway administrator or external market participants in a differentiated manner.

[0008] During the certification of a smart meter gateway (SMGW), care is taken to ensure that the secure communication channels provided by the SMGW cannot be compromised, thus preventing any interference with the transmitted measurement data and switching operations. However, communication with the SMGW could be deliberately disrupted by a compromised network management system (NwMgmt), which could prevent service availability and ultimately affect the stability of the entire power grid.

[0009] The object of the invention is therefore to provide a smart meter gateway and a method for operating a smart meter gateway on or with which network management with improved security can be operated.

[0010] This problem is solved by a smart meter gateway with the features of claim 1 and a method for operating a smart meter gateway with the features of claim 5. Advantageous further developments of the invention are the subject of the respective dependent claims.

[0011] The smart meter gateway according to the invention includes a cellular module configured to transmit measurement data to an authorized recipient via a cellular network. More precisely, the cellular module typically provides an "unsecured" LTE connection for data transmission, which is used by the smart meter gateway to establish several "secure" TLS channels for communication.

[0012] Furthermore, the smart meter gateway according to the invention comprises a processor that interacts with working memory and / or flash memory to run, in particular, application software for SMGWs on an operating system. This software reads out measurement data, encrypts it, and transmits it to the mobile communication module for forwarding to the authorized recipient. Programs for logging and process control can also run on the operating system. All these functions can be combined into a single application software for SMGWs.

[0013] Typically, the processor, main memory and / or flash memory form the essential components of the Target of Evaluation and are designed to comply with the Protection Profile for the SMGW.

[0014] The mobile communication module also includes an embedded system (a combination of hardware and software designed to perform this function within the larger mobile communication module system) configured to operate a network management client. When operational, this network management client communicates with a network management server via the mobile network.

[0015] A key aspect of the invention is that an additional security module is directly connected to the mobile communication module, with which the network management client interacts to communicate with the network management server in encrypted form. This additional security module serves to provide security-relevant functionalities; in particular, it performs high-entropy random number generation, provides secure key storage, and offers a basis for implementing encryption methods. Preferably, this security module meets the requirements of EAL 6+ level according to the Common Criteria (CC).

[0016] Directly connected means, in particular, that the security module is located on the same circuit board as the mobile communication module and communicates directly with it. It may also be implemented on the mobile communication module itself, but in that case, it must not be involved in the module's other operations and / or may only be used for implementing proprietary algorithms.

[0017] Components of the Smart Meter Gateway from its TOE, which offer such functions to, for example, provide encrypted transmission of metering data, are not directly connected to the mobile communication module.

[0018] The inclusion of an additional security module directly connected to the mobile communication module secures communication independently during the operation of the network management client and can thus significantly reduce security risks arising from this operation. In particular, such a security module allows for a high degree of control over encryption algorithms and keys and enables security certification.

[0019] In a preferred advanced training, the mobile communication module of the smart meter gateway is connected via a serialized USB interface. This interface—particularly within the TOE (Total Equipment Interface)—is designed so that no commands can be sent from the modem to the processor. This is achieved primarily by the processor software not accepting command calls from this interface. This provides an additional safeguard against third-party interference with the proper functioning of the system.

[0020] Due to the associated increase in security, it is still preferred if the mobile communication module is configured to have a first communication channel for communication with the authorized recipient and a second communication channel for communication with the network management server, so that the WAN connection for network management is completely separated from the WAN connection used for metering operation.

[0021] Another advantageous feature is that the cellular module is configured for both AT commands sent from the processor to the cellular module and configuration by the network management client. This allows the smart meter gateway to be properly commissioned even if it is not yet integrated into a network management system.

[0022] The method according to the invention serves to operate a smart meter gateway with a mobile communication module to which a security module is directly connected, and with a processor that interacts with main memory and / or flash memory to run application software for smart meter gateways on an operating system, wherein the mobile communication module further comprises an embedded system. In the method, measurement data, in particular from consumption metering points, is read out by the application software for smart meter gateways and encrypted before being transmitted to the mobile communication module for forwarding to an authorized recipient. Furthermore, in the method, a network management client is operated on the mobile communication module using the embedded system, which communicates with a network management server via the mobile network.Essential to the method according to the invention is that the communication between the network management client and the network management server is encrypted using the security module directly connected to the mobile communication module. This secures the communication independently during the operation of the network management client and can thus significantly reduce security risks arising from this operation. In particular, the use of encryption with such a security module allows for a high degree of control over encryption algorithms and keys and enables security certification.

[0023] Preferably, the mobile communication module is configured either via AT commands from the processor or via the network management client. This ensures proper commissioning of the smart meter gateway even if it is not yet integrated into the network management system.

[0024] Furthermore, it is preferable for network management communication to take place via a separate communication channel with a separate target network, e.g., using Dual APN on LTE technology. This measure also reduces the vulnerability of the smart meter gateway to third-party attacks.

[0025] In a preferred embodiment of the invention, the method uses a standard network management protocol, in particular SNMP or LwM2M, to provide the network management functionality. This allows the monitoring and configuration of parameters important for the operation of the SMGW.

[0026] Because the implementation, including encryption, is carried out independently and does not rely on built-in encryption mechanisms of the LTE module itself, the disclosure of the source code, which is necessary to demonstrate compliance with security requirements and / or for certification, becomes possible, unlike when using special, proprietary solutions.

[0027] Preferably, strong encryption methods are used for encryption with the security module directly connected to the mobile communication module.

[0028] It is also preferred that the complete source code of the software for operating the smart meter gateway, including the mobile communication module, be disclosed for certification.

[0029] The invention is explained in more detail below with reference to a figure.

[0030] Figure 1 shows an example implementation of a smart meter gateway.

[0031] The in Figure 1 The depicted Smart Meter Gateway 1 has a Target of Evaluation 2, which comprises a processor 3 that interacts with a working memory 4 and a flash memory 5. A mobile communication module 9 is connected via a serialized USB interface 8, which allows command execution only from within the Target of Evaluation 2.

[0032] The mobile communication module 9 includes a modem 10 and an embedded system 11 on which a network management client 12 is run, implementing a standard network management protocol such as SNMP or LwM2M.

[0033] An additional security module 13 is directly connected to the mobile communication module 9, which in this embodiment meets the EAL 6+ security level of the Common Criteria (CC) and in particular provides the security-relevant functionalities for encryption, including in particular high entropy random number generation, the provision of basic encryption methods and a secure storage for keys.

[0034] The additional security module 13 works together with the network management client 12 to communicate encrypted via the mobile network 14, the network management APN (access point) 15 and the internal network management network 16 with its backend server, the network management server 17.

[0035] The processor 3 works in particular with the main memory 4 and the flash memory 5 to run application software for SMGWs 19 on an operating system 18, with which measurement data, in particular from devices from a local metrological network, is read and encrypted for forwarding to the authorized recipient via the mobile communication module 9, which communicates with its backend server, the metering server 22, via the modem 10 and the mobile network 14 as well as the metering APN (access point) 20 and the internal metering network 21, and thereby forwards the measurement data read by the application software for SMGWs 19 in encrypted form to the authorized recipient.

[0036] Accordingly, when operating the Smart Meter Gateway 1, the following applies: Figure 1The WAN connection for network management is completely separated from the WAN connection used for metering operations, and network management communication takes place via a separate communication channel. Reference symbol list

[0037] 1 Smart Meter Gateway 2 Target of Evaluation 3 Processor 4 RAM 5 Flash Memory 8 Serialized USB Interface 9 Mobile Radio Module 10 Modem 11 Embedded System 12 Network Management Client 13 Additional Security Module 14 Mobile Radio Network 15 Network Management APN 16 Network Management Network 17 Network Management Server 18 Operating System 19 Application Software for SMGWs 20 Metering APN 21 Metering Network 22 Metering Server

Claims

1. Smart meter gateway (1) comprising a mobile radio module (9) which is configured to exchange power supply-specific data with an authorised receiver via a mobile radio network (14), and comprising a processor (3) which interacts with a working memory (4) and / or a flash memory (5) in order to operate application software for SMGWs (19) on an operating system (18), with which software measurement data are read out and delivered to the mobile radio network (9) encrypted for forwarding to the authorised receiver, wherein the mobile radio module (9) further comprises an embedded system (11) which is configured for operating a network management client (12) which communicates with a network management server (17) via the mobile radio network (14), and an additional security module (13) is connected directly to the mobile radio module (9), with which security module the network management client (12) interacts in order to communicate in an encrypted manner with the network management server (17).

2. Smart meter gateway (1) according to claim 1, characterised in that the mobile radio module (9) is connected via a serial USB interface (8) in such a way that no commands can be directed from the mobile radio interface (9) to the processor (3).

3. Smart meter gateway (1) according to claim 1, characterised in that the mobile radio module (9) is configured in such a way that it comprises a first communication channel for communication with the authorised receiver and a second communication channel for communication with the network management server (17), such that the network management network is completely separated from the metering network.

4. Smart meter gateway (1) according to any of claims 1 to 3, characterised in that the mobile radio module (9) is designed both for a configuration by AT commands that are directed from the processor (3) to the mobile radio module (9) and for a configuration by the network management client (12).

5. Method for operating a smart meter gateway (1) comprising a mobile radio module (9) to which a security module (13) is directly connected, and comprising a processor (3) which interacts with a working memory (4) and / or a flash memory (5) in order to operate application software for SMGWs (19) on an operating system (18), wherein the mobile radio module (9) further comprises an embedded system (11), wherein in the method the application software for SMGWs (19) reads out measured data and delivers said data encrypted to the mobile radio module (9) for forwarding to an authorised receiver, and a network management client (12) is operated with the embedded system (11) on the mobile radio network (9), which client communicates with a network management server (17) via the mobile radio network (14), wherein the communication between the network management client (12) and the network management server (17) is encrypted with the aid of the security module (13) that is directly connected to the mobile radio module (9).

6. Method according to claim 5, characterised in that the configuration of the mobile radio module (9) takes place selectively by AT commands of the processor (3) or by the network management client (12).

7. Method according to either claim 5 or claim 6, characterised in tat the network management communication takes place via a separate communication channel with a separate target network.

8. Method according to any of claims 5 to 7, characterised in that a standard network management protocol is used for providing the network management functionality.

9. Method according to any of claims 5 to 8, characterised in that strong encryption methods are used for the encryption with the security module (13) that is directly connected to the mobile radio module (9).

10. Method according to any of claims 5 to 9, characterised in that the complete source code of the software for operating the smart meter gateway (1), including the network management application, is published for certification.