Method for starting a control component of an automation system, control component and automation system

Abstract

Method for starting a control component (120, 130, 140) of an automation system (100) comprising a plurality of control components (120, 130, 140), wherein the control components are each designed as a programmable logic controller, numerical controller or motion controller and are real-time capable, wherein during a start-up process it is automatically checked whether the control component (120, 130, 140) has an individual cryptographic identification feature (125, 135, 145), wherein, if the control component (120, 130, 140) has an individual cryptographic identification feature (125, 135, 145), the start-up process is continued, and wherein, if the control component (120, 130, 140) does not have an individual cryptographic identification feature, an individual cryptographic identification feature (125, 135, 145) is automatically generated and the start-up process is subsequently continued.

Description

[0001] The present invention relates to a method for starting a control component of an automation system comprising a plurality of control components, to such a control component and to such an automation system. State of the art

[0002] In automation technology, automation systems are used that comprise several individual control components or control units (especially so-called PLCs, programmable logic controllers). Such automation systems are used, for example, in production or manufacturing and, depending on the application, can comprise various control components, which in turn perform different functions or activities.

[0003] For example, it is known from US 2015 / 0363543 A1 that a list of control components used can be created for an automation system so that the control components can perform certain operations.

[0004] From US 2014 / 0229015 A1, for example, it is known that a configuration file can be created which can be used to identify control components with which communication is to take place.

[0005] For example, it is known from US 9 030 315 B2 that identifiers are used for communication between two control components, with one component receiving the identifier of the other. US 2015 / 0169875 A1 describes the creation of an identity for computers in a network. DE 10 2014 206 989 A1 discloses an automation system. Disclosure of the invention

[0006] According to the invention, a method for starting a control component of an automation system, a control component, and an automation system are proposed with the features of the independent patent claims. Advantageous embodiments are the subject of the subclaims and the following description.

[0007] A method according to the invention is used for starting, i.e., booting up, a control component of an automation system comprising a total of several control components. For this purpose, an automated check is carried out during a start-up process to determine whether the control component has an individual cryptographic identification feature that is suitable for use in cryptographic methods and, in particular, is not known to all other control components. An individual cryptographic identification feature can be understood to be an identification feature that is different from the identification features of the other control components of the automation system. A cryptographic identification feature can, for example, be a digitally readable numeric and / or letter code.If the control component now has an individual cryptographic identification feature, the startup process continues. Otherwise, i.e., if the control component does not have an individual cryptographic identification feature, an individual identification feature is automatically generated, and then the startup process continues. Automated verification or generation here means that the corresponding process occurs without external or manual intervention. The control component can be programmed accordingly for this purpose.

[0008] In this way, a control component of an automation system can be assigned an individual cryptographic identification feature immediately after startup, i.e., as soon as it is ready for use, by which it can be uniquely identified within the automation system. This allows, for example, the control component to be addressed specifically later or a targeted and secure (encrypted and / or signed) exchange of data, especially process data, can take place.

[0009] In comparison to previous procedures, in which the individual control components had no or at least no secret cryptographic identification features after startup, since these were initially stored externally during the production of the control component, for example, it is no longer necessary to manually change or apply the cryptographic identification features during installation or during subsequent operation within the automation system.

[0010] This also offers an advantage over cases where, for example, keys are generated during production or made available via a public key infrastructure. The risk there is that the key can be stolen during generation. Automated generation prevents this from happening.

[0011] Conveniently, all control components of such an automation system can then be started in the same way as described for a control component.

[0012] Preferably, the individual cryptographic identification feature is generated based on at least one parameter selected from: a serial number, a time of day, a temperature, a random number generated by hardware, and a random number generated by software. All of these parameters differ from one another for different control components and thus enable the simple generation of an individual cryptographic identification feature.

[0013] The serial number of a device or component is, on the one hand, individual for the device or component and, on the other hand, usually also stored digitally. The serial number of the control component is expediently considered as the serial number here. However, a serial number of a part of the control component or a combination of several such serial numbers is also conceivable. The time, in particular during or at the start of the generation of the identification feature, is different for different control components when the individual control components are started one after the other. The temperature of the control components or at a certain point on the control component, where it is measured, for example, using a temperature sensor, differs from the temperature of other control components at least within a decimal point. The inaccuracy of the temperature sensor, for example, also contributes to this.Likewise, random numbers differ, at least with a sufficiently high probability, between different control components. For example, when generating a certificate as a cryptographic identification feature, one or more (or all) unique parameters can be included in addition to a public key (e.g., of a higher-level control system).

[0014] Advantageously, a key pair consisting of a private and a public key is generated using the individual cryptographic identification feature. An asymmetric method such as the RSA method is suitable for this purpose. Such cryptographic methods enable particularly simple and effective encryption and certification for secure communication.

[0015] In this respect, it is also advisable to generate a cryptographic certificate using the public key, for example, a so-called X.509 certificate. This is a common and simple certificate. In this context, it is also advisable to transfer the cryptographic certificate and / or the public key to a public directory service and, in particular, to sign it there, as this allows for particularly secure encryption. With regard to the private key, it is advantageous if it is stored automatically in the control component. Using the options mentioned, secure encryption can be provided for the control component.

[0016] It is advantageous if the individual cryptographic identification feature is used as the basis for communication and / or data exchange with another of the multiple control components and / or with a higher-level control and / or operating unit. In conjunction with the encryption options mentioned, such communication or data exchange can also be made very secure, resulting in an overall secure automation system. The individual cryptographic identification feature can thus be used both to identify the control component and as the basis for communication or encryption.

[0017] A control component according to the invention for an automation system comprising a plurality of control components is configured to carry out a method according to the invention. The control components can be configured accordingly for this purpose, in particular in terms of programming. This involves a programmable logic controller (PLC), numerical control (NC) or CNC control (computerized numerical control), or motion control (MC). In addition, the control component is real-time capable, i.e., individual calculation steps are completed within defined time periods. In real-time capable environments, it can be guaranteed that a calculation result is available in a timely manner, so that, particularly in automation systems, the movements of different units also run synchronously.

[0018] An automation system according to the invention accordingly comprises several control components according to the invention. It is understood that the individual intended uses of the respective control components within the automation system can be, and usually are, different. However, such an automation system is ready for use immediately after booting up, without any additional effort, particularly manual effort.

[0019] Implementing the method in the form of a computer program is also advantageous, as this results in particularly low costs, especially if an executing control component is also used for other tasks and is therefore already present. Suitable data storage media for providing the computer program include, in particular, magnetic, optical, and electrical storage devices, such as hard disks, flash memories, EEPROMs, DVDs, and others. Downloading a program via computer networks (Internet, intranet, etc.) is also possible.

[0020] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0021] The invention is illustrated schematically in the drawing using an embodiment and is described in detail below with reference to the drawing. Character description Fig. 1 schematically shows an automation system according to the invention in a preferred embodiment. Fig. 2 shows schematically a sequence of a method according to the invention in a preferred embodiment. Detailed description of the drawing

[0022] In Fig. Figure 1 schematically illustrates an automation system 100 according to the invention in a preferred embodiment. The automation system 100 comprises, for example, a production line 110 along which three control components 120, 130, and 140 are arranged.

[0023] Each of these control components can be assigned an independent task within a production process. These control components can be, for example, PLCs or similar devices. These controllers meet the real-time requirements to ensure deterministic control of production processes, such as newspaper printing or food packaging printing.

[0024] Furthermore, a higher-level control unit 150 is shown, here exemplified in the form of a PC. The control components 120, 130, and 140, as well as the control unit 150, each have a communication unit, here exemplified by fieldbus interfaces, e.g., for Sercos, Profibus, etc., via which communication is possible between the individual control components and between each of the control components and the control unit 150. For the control components 120, 130, and 140, the communication units are designated by reference numerals 121, 131, and 141, respectively.

[0025] Furthermore, each of the control components 120, 130, and 140 has an individual cryptographic identification feature 125, 135, and 145, respectively. These identification features are different from one another. For a possible generation of the individual cryptographic identification features and possible types of the individual identification features, please refer to the following description.

[0026] In Fig. 2 is a schematic representation of a process according to the invention in a preferred embodiment, as it is for example for each or with each of the Fig. 1 shown control components.

[0027] In step 200, the control component is first started. Such a start-up process can be initiated, for example, during commissioning of the entire automation system.

[0028] In step 210, during the startup process, it is checked whether an individual cryptographic identification feature - also referred to as control identity - is present in the control component.

[0029] If it is determined in step 210 that an individual cryptographic identification feature is already present, which was generated, for example, in a previous boot process, the process proceeds to step 230, ie the boot process is continued without a new generation of an individual cryptographic identification feature.

[0030] If it is determined in step 210 that no individual cryptographic identification feature is present, the system proceeds to step 220. In step 220, an individual cryptographic identification feature is generated for the control component and advantageously stored in a secure memory, in particular one that cannot be read externally.

[0031] To generate the individual cryptographic identification feature, various parameters can be used, allowing the creation of an identification feature that differs from those of the other control components. As already mentioned, such parameters include, for example, the serial number of the control component and / or a component thereof, the current time, the temperature of the control component or at a specific location on the control component, and / or random numbers generated based on hardware and / or software.

[0032] The identification feature can then also be used for an encryption method, such as the RSA method, which includes a private and public key. While the private key can remain on the control component for later communication, the public key can be transmitted to the control unit and via it, or directly to a public directory service for signature. Likewise, a certificate can be generated using the public key, which can be used for later communication.

[0033] After the individual cryptographic identification feature has been generated, it is now possible to proceed to step 230, ie the start-up process can continue.

[0034] The described procedure can be performed on each control component. This ensures that after booting, each control component has an individual cryptographic identification feature, based on which the individual control components can now be identified within the automation system.

[0035] This enables targeted communication and data exchange, for example for process data that is generated or accumulated during operation, on the one hand between different control components and on the other hand between a control component and the operating unit.

[0036] For the communication itself, secure communication can also be established using individual cryptographic identification features or the associated keys or certificates. Likewise, a specific control component can be addressed directly via the control unit. Manual assignment of individual identification features is no longer necessary.

Claims

[1] Method for starting a control component (120, 130, 140) of an automation system (100) comprising a plurality of control components (120, 130, 140), wherein the control components are each designed as a programmable logic controller, numerical controller or motion controller and are real-time capable, wherein during a start-up process it is automatically checked whether the control component (120, 130, 140) has an individual cryptographic identification feature (125, 135, 145), wherein, if the control component (120, 130, 140) has an individual cryptographic identification feature (125, 135, 145), the start-up process is continued, and wherein, if the control component (120, 130, 140) does not have an individual cryptographic identification feature, an individual cryptographic identification feature (125, 135, 145) is automatically generated and the start-up process is subsequently continued. [2] The method of claim 1, wherein the individual cryptographic identification feature (125, 135, 145) is generated based on at least one characteristic selected from: a serial number, a time of day, a temperature, a hardware-generated random number, and a software-generated random number. [3] Method according to claim 1 or 2, wherein a key pair comprising a private key and a public key is generated using the individual cryptographic identification feature (125, 135, 145). [4] The method of claim 3, wherein a cryptographic certificate is generated using the public key. [5] Method according to claim 4, wherein the cryptographic certificate is transmitted to a public directory service and in particular is signed there. [6] Method according to one of claims 3 to 5, wherein the public key is transmitted to a public directory service and in particular is signed there. [7] Method according to one of claims 3 to 6, wherein the private key is automatically stored in the control component (120, 130, 140). [8] Method according to one of the preceding claims, wherein the individual cryptographic identification feature (125, 135, 145) is used as a basis for communication and / or data exchange with another of the plurality of control components (120, 130, 140) and / or with a higher-level control and / or operating unit (150). [9] Method for starting all control components (120, 130, 140) of an automation system (100) comprising a plurality of control components (120, 130, 140), wherein each of the control components (120, 130, 140) is started according to a method according to one of the preceding claims. [10] Control component (120, 130, 140) for an automation system (100) comprising a plurality of control components (120, 130, 140) which is configured to carry out a method according to one of the preceding claims, wherein the control components are each designed as a programmable logic controller, numerical controller or motion controller and are real-time capable. [11] Automation system (100) with a plurality of control components (120, 130, 140) according to claim 10. [12] Computer program which causes a control component (120, 130, 140) to carry out a method according to one of claims 1 to 9 when executed on the control component (120, 130, 140). [13] A machine-readable storage medium having stored thereon a computer program according to claim 12.

Images