DE102014226388A1 - Configuration device and method for configuring field devices - Google Patents

Abstract

A configuration device for configuring a number of field devices which can be coupled by means of an automation network is proposed. The respective field device has a random number generator for generating a random number for generating cryptographic data. The configuration device comprises a delivery unit and a transfer unit. The provisioning unit is set up to provide configuration data for the respective field device. The configuration data includes configured data and a seed value for initializing the random number generator of the field device. The transmission unit is set up to transmit the provided configuration data via the automation network to the field device. This makes it possible to provide field devices, which do not have their own source of good chance, by means of the starting value with an initial entropy. Furthermore, a method for configuring field devices, such a field device and a system with field devices and a configuration device are proposed.

Description

The present invention relates to a configuration device for configuring field devices. Furthermore, the present invention relates to a method for configuring field devices, such a field device and a system with field devices and a configuration device.

The field device comprises a random number generator for generating a random number. The random number is used in the field device for generating cryptographic data. Examples of cryptographic data are a cryptographic key or a nonce.

Random numbers provide a foundation in cryptography, such as key management for security services, such as integrity protection or encryption of data. In particular, random numbers are needed to generate the cryptographic key or to determine the nonce. Random numbers can be generated by logical random number generators or physical random number generators. Strong random numbers are often generated by or using a physical random number generator.

However, field devices, such as sensors or actuators that have a random number generator, often do not have a suitable source of "randomness" to properly initialize the random number generator via a seed value. Consequently, there is a need to provide field devices with suitable good seeds, so-called seeds, for the local random number generator of the field device.

In the document US 20060072747 A1 describes an external server for providing additional entropy.

In this case, the transmission of the start value to the device is protected by means of a SSL / TLS connection using a temporary key pair of the device.

From the document WO 2014091336 A1 It is known to supply a field device with access data to an external random number generator during the engineering. The field device can use this access data to connect to the external source and to query starting values (seeds) in a secure manner.

Against this background, an object of the present invention is to improve the configuration of field devices.

According to a first aspect, a configuration device for configuring a number of field devices which can be coupled by means of an automation network is proposed. The respective field device has a random number generator for generating a random number for generating cryptographic data. The configuration device comprises a delivery unit and a transfer unit. The provisioning unit is set up to provide configuration data for the respective field device. The configuration data includes configured data and a seed value for initializing the random number generator of the field device. The transmission unit is set up to transmit the provided configuration data via the automation network or via a serial configuration interface to the field device. It is also possible that configuration information is written to a changeable configuration memory module of a field device.

The proposed configuration device makes it possible to provide field devices, such as industrial field devices or control devices, which do not have their own source of good chance, with an initial entropy by means of the starting value. This enables the generation of "good" or strong random numbers during operation of the field device without the need for an individual supply of the field device with entropy during production.A start value for a random number generator is in a configuration process of the field device, which is required anyway for commissioning anyway, In addition, it is not necessary to provide a physical random number generator on the field device.The field device preferably stores the provided start value or information dependent thereon in a non-volatile memory to generate a sequence of random numbers by means of a logical random number generator.

According to one embodiment, the configuration device has a random number generator for generating the starting value for initializing the random number generator of the field device.

The seed is generated by the random number generator configuration device and provided to the field device as part of the configuration data. This has the advantage that in the case of a plurality of field devices that are functionally identically configured, a separate configuration per field device does not have to be carried out. The random number generator of the configuration device may generate the seed value, for example, as a hash value using a cryptographic hash function such as SHA2, SHA3 or BLAKE.

According to a further embodiment, the automation network forms a local connection between the number of field devices and the configuration device. Alternatively, the automation network can also form a remote connection between the configuration device and the number of field devices.

According to a further embodiment, the start value is transmitted encrypted by the configuration device to the field device. For this a symmetric encryption can be used.

According to a further embodiment, the starting value is transmitted to the field device via an authenticated and encrypted channel. Authentication can be symmetric or asymmetrical.

According to a further embodiment, the random number generator of the configuration device is designed as a physical random number generator.

The physical random number generator of the configuration device may provide strong random numbers as a seed. The central physical random number generator of the configuration device can be used for all connected field devices. Consequently, it is not necessary to provide a physical random number generator on the field devices.

According to a further embodiment, the random number generator of the field device is designed as a pseudo-random number generator.

The pseudo-random number generator can use the high entropy provided by the physical random number generator of the configuration device for its initialization and thus provide higher quality random numbers.

According to a further embodiment, the providing unit is designed to form the configuration data from the field device specific configured data and the starting value for initialization of the random number generator of the field device.

The configured data can be configured specifically for the respective field device or for a group of field devices.

According to a further embodiment, the configuration device has a loading unit, which can be coupled via a network to a server for providing random values and which is set up to download a random value from the server. In this case, the providing unit is set up to form the starting value for initializing the random number generator of the field device as a function of the downloaded random value.

The server for providing random values may also be referred to as a random server. The random values provided by the random server are in particular strong random values. Thus, a high proportion of entropy can be taught when generating the initial value for the initialization of the random number generator of the field device.

According to a further embodiment, the configuration device sends a device identifier of the field device to the server (random server) in order to generate a device-specific start value.

According to another embodiment, the random number generator uses a device certificate transmitted by the field device to encrypt the start value. This encrypted container is then returned to the configuration device and inserted into the configuration data. This has the advantage that the start value is protected on the complete transport route. In addition, the random number generator can already precalculate the seed containers with knowledge of the device certificates.

In accordance with a further embodiment, the provisioning unit is set up to use the downloaded random value as the starting value for initializing the random number generator of the field device.

This embodiment has the advantage of a very simple implementation.

According to a further embodiment, the providing unit is configured to calculate the starting value for initializing the random number generator of the field device as a function of the downloaded random value and of at least one parameter provided by an entropy source.

This embodiment has the advantage of increasing the entropy for the start value and thus increasing the quality of the random numbers generated by the random number generator of the field device.

According to a further embodiment, the configuration device has a combination unit which is set up to initialize the random number generator of the field device by a combination of a random value generated by the random number generator of the configuration device and to combine random value downloaded from the server.

The combination increases the entropy and thus the quality of the random numbers to be generated.

In accordance with a further embodiment, the provision unit is set up to form the configuration data to be transmitted to the field device from the configured data and a new start value for initializing the random number generator of the field device during each loading operation of configured data.

The configuration device preferably generates a seed, which is provided to the field device, during each loading or deployment process. That is, even if the same field device is provided with projected data multiple times, each deployment process includes a new, generally different seed in the provided configuration data.

According to a further embodiment, the configuration device is configured to authenticate itself to the field device and to authenticate the field device.

The field device and the configuration device authenticate themselves on both sides. For example, then the field device acts as a server and the configuration device as a client.

According to another embodiment, the cryptographic data is designed as a cryptographic key.

According to a further embodiment, the cryptographic data are formed as a nonce.

The respective unit, for example, provision unit or transmission unit, can be implemented in terms of hardware and / or software technology. In a hardware implementation, the respective unit may be embodied as a device or as part of a device, for example as a computer or as a microprocessor or as an integrated circuit. In a software implementation, the respective unit may be designed as a computer program product, as a function, as a routine, as part of a program code or as an executable object.

According to a second aspect, a field device is proposed. The field device has a random number generator for generating a random number for generating cryptographic data, a coupling unit for coupling the field device with a configuration device for configuring the field device via an automation network, and an initialization unit for initializing the random number generator by means of a transmitted from the configuration device and received via the coupling unit start value.

According to a third aspect, a system is proposed. The system comprises a number, in particular a plurality of field devices according to the second aspect and a configuration device according to the first aspect.

According to a fourth aspect, a method for configuring a number of field devices which can be coupled by means of an automation network is proposed. The respective field device comprises a random number generator for generating a random number for generating cryptographic data. The method comprises the following steps:
Providing a start value for initializing the random number generator of the field device,
Formation of configuration data from configured data and the provided start value, and
Transferring the configuration data formed, for example via the automation network, to the field device.

According to a development, the start value is transmitted in encrypted form to the field device.

Alternatively or additionally, the starting value can be transmitted to the field device via an authenticated and encrypted channel. Authentication can be symmetric or asymmetrical.

The embodiments and features described for the proposed configuration device apply correspondingly to the proposed method.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of preferred embodiments with reference to the attached figures.

1 shows a schematic block diagram of a first embodiment of a configuration device for configuring field devices;

2 shows a schematic block diagram of configuration data for configuring a field device;

3 shows a schematic block diagram of a second embodiment of a configuration device for configuring field devices;

4 shows a schematic block diagram of a third embodiment of a configuration device for configuring field devices;

5 shows a schematic block diagram of a fourth embodiment of a configuration device for configuring field devices; and

6 shows a schematic flow diagram of an embodiment of a method for configuring field devices.

In the figures, the same or functionally identical elements have been given the same reference numerals, unless stated otherwise.

1 shows a schematic block diagram of a first embodiment of a configuration device 10 for configuring a number by means of an automation network 20 coupling field devices 30 ,

Without restriction of generality shows 1 a field device 30 , It can be a plurality of field devices 30 via the automation network 20 with the configuration device 10 be coupled.

The field device 30 includes a random number generator 31 for generating a random number ZZ for generating cryptographic data. In addition, the field device includes 30 a coupling unit 32 for coupling the field device 30 with the automation network 20 and thus with the configuration device 10 over that automation network 20 , In addition, the field device points 30 an initialization unit 33 which is adapted to the random number generator 31 by means of one of the configuration device 10 sent and via the coupling unit 32 received initial value SW to initialize. The random number generator 31 generates a random number ZZ. Furthermore, the field device includes 30 a control device 34 to control the same. The control device 34 is adapted to cryptographic data by means of the random number generator 31 generate generated random number ZZ. Furthermore, the controller uses 34 configured data PD for controlling the field device 30 or to perform its function.

For this purpose, the configuration device 10 a deployment unit 11 and a transmission unit 12 on. The delivery unit 11 is set up, the configuration data KD for the field device 30 provide. The provided configuration data KD comprises configured data PD and the starting value SW for initializing the random number generator 31 of the field device 30 (please refer 2 ). The configured data PD are projected in advance by a project engineer or an engineer, can also be referred to as configuration data and are intended to be applied to the field device 30 be played.

The delivery unit 11 In particular, it is set up for each loading operation of configured data PD that is sent to the field device 30 to be transmitted configuration data KD from the configured data PD and a new start value SW for initialization of the random number generator 31 of the field device 30 to build. Accordingly, the start value SW is regenerated for each load. The configured data PD can change from charging to charging or remain the same.

The transmission unit 12 is set up to provide the configuration data KD via the automation network 20 or via a serial configuration interface (not shown) to the field device 30 transferred to. It is also possible that the configuration data KD to a removable configuration memory module of the field device 30 to be written.

In addition, the configuration device 10 especially adapted to the field device 30 to authenticate and the field device 30 to authenticate. Consequently, the two devices, namely the configuration device 10 and the field device 30 to authenticate each other and increase the security of communication.

The cryptographic data is for example a cryptographic key or a nonce.

3 shows a schematic block diagram of a second embodiment of a configuration device 10 , The second embodiment of the 3 includes all features of the first embodiment of the configuration device 10 of the 1 and additionally a random number generator 13 , The random number generator 13 is to configured to generate the seed value SW and to the provisioning unit 11 transferred to. The delivery unit 11 adds that from the random number generator 13 generated start value SW the configuration data KD for the field device 30 at. The random number generator 13 is in particular a physical random number generator and provides strong random numbers. In contrast, the random number generator 31 of the field device 30 for example, formed as a pseudo-random number generator and provides pseudo-random numbers ready.

4 shows a schematic block diagram of a third embodiment of a configuration device 10 for configuring field devices 30 ,

The third embodiment of 4 comprises all the features of the second embodiment of the 3 , Furthermore, the configuration device comprises 10 of the 4 a loading unit 14 as well as an entropy source 15 , The entropy source 15 can also be outside the configuration device 10 be arranged. The entropy source 15 provides a quasi-random parameter P. This quasi-random parameter P is, for example, the current temperature of the environment of the configuration device 10 derived. The quasi-random parameter P may also depend on the data traffic of the configuration device 10 or the like derived.

The loading unit 14 is over a network 40 with a server 50 coupled. The network 40 can be a local network or the internet. The server 50 is set up to provide random values ZW. The loading unit 14 loads a random value ZW from the server 50 over the network 40 down and sets the downloaded random value ZW of the deployment unit 11 ready. The delivery unit 11 is adapted to the initial value SW for initialization of the random number generator 31 of the field device 30 depending on the downloaded random value ZW. For example, the deployment unit uses 11 the downloaded random value ZW as the starting value SW, and adds this random value ZW to the configuration data KD.

Alternatively, the delivery unit 11 Also be set to the starting value SW for initialization of the random number generator 31 depending on the downloaded random value ZW and depending on the entropy source 15 provided parameter P.

In 5 is a schematic block diagram of a fourth embodiment of a configuration device 10 for configuring field devices 30 shown. The fourth embodiment of 5 is based on the third embodiment of 4 , Furthermore, the configuration device has 10 of the 5 a combination unit 16 which, for example, in the delivery unit 11 is integrated. The combination unit 16 is adapted to the initial value SW for initialization of the random number generator 31 of the field device 30 by a combination of one by the random number generator 13 the configuration device 10 generated random value ZW1 and one from the server 50 downloaded random value ZW2 to combine.

6 shows a schematic flow diagram of an embodiment of a method for configuring a number of means of an automation network 20 coupling field devices 30 , The field device 30 is like in one of the 1 . 2 or 4 educated.

The procedure of 6 includes the following process steps 601 - 603 :

In step 601 becomes a start value SW for initializing the random number generator 31 of the field device 30 provided.

In step 602 Configuration data KD for the field device 30 formed from configured data PD and the provided start value SW.

In step 603 become the formed configuration data KD, for example via the automation network 20 , on the field device 30 transfer.

The steps 601 - 603 for example, from a configuration device 10 of the 1 . 3 or 4 executed.

Although the present invention has been described with reference to embodiments, it is variously modifiable.

LIST OF REFERENCE NUMBERS

10

contraption

11

Providing unit

12

transmission unit

13

Random number generator

14

charging unit

15

entropy

16

combination unit

20

Automation network

30

field device

31

Random number generator

32

coupling unit

33

initialization

34

control device

40

network

50

server

KD

configuration data

P

parameter

PD

configured data

SW

start value

ZW

random value

ZZ

random number

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 20060072747 A1 [0005]
• WO 2014091336 A1 [0007]

Claims (15)

Configuration device ( 10 ) for configuring a number of by means of an automation network ( 20 ) connectable field devices ( 30 ), whereby the respective field device ( 30 ) a random number generator ( 31 ) for generating a random number (ZZ) for generating cryptographic data, comprising: a provision unit ( 11 ) for providing configuration data (KD) for the respective field device ( 30 ), wherein the configuration data (KD) projected data (PD) and a start value (SW) for initializing the random number generator ( 31 ) of the field device ( 30 ) and a transmission unit ( 12 ) for transferring the provided configuration data (KD) to the field device ( 30 ). Configuration device according to Claim 1, characterized by a random number generator ( 13 ) for generating the starting value (SW). Configuration device according to claim 2, characterized in that the random number generator ( 13 ) of the configuration device ( 10 ) is designed as a physical random number generator and / or the random number generator ( 31 ) of the field device ( 30 ) is formed as a pseudo-random number generator. Configuration device according to one of claims 1-3, characterized in that the provisioning unit ( 11 ) is adapted to the configuration data (KD) for the field device ( 30 ) specific configured data (PD) and the starting value (SW) for initializing the random number generator ( 31 ) of the field device ( 30 ) to build. Configuration device according to one of claims 1-4, characterized by a loading unit ( 14 ), which are connected via a network ( 40 ) with a server ( 50 ) is adapted to provide random values (ZW) and which is adapted to generate a random value (ZW) from the server (ZW). 50 ), whereby the deployment unit ( 11 ) is set to the initial value (SW) to initialize the random number generator ( 31 ) of the field device ( 30 ) depending on the downloaded random value (ZW). Configuration device according to claim 5, characterized in that the provisioning unit ( 11 ) is set up to use the downloaded random value (ZW) as the starting value (SW) for initializing the random number generator ( 31 ) of the field device ( 30 ) to use. Configuration device according to claim 5, characterized in that the provisioning unit ( 11 ) is set to the initial value (SW) to initialize the random number generator ( 31 ) of the field device ( 30 ) depending on the downloaded random value (ZW) and at least one of an entropy source ( 15 ) (P). Configuration device according to one of Claims 5 to 7, characterized by a combination unit ( 16 ), which is adapted to the initial value (SW) for initialization of the random number generator ( 31 ) of the field device ( 30 ) by a combination of a random number generator ( 13 ) of the configuration device ( 10 ) generated random value (ZW1) and that of the server ( 50 ) to combine downloaded random value (ZW2). Configuration device according to one of claims 1-8, characterized in that the provisioning unit ( 11 ) is set up for each loading of projected data (PD) to the field device ( 30 ) to be transmitted configuration data (KD) from the configured data (PD) and a new start value (SW) for initialization of the random number generator ( 31 ) of the field device ( 30 ) to build. Configuration device according to one of claims 1-9, characterized in that the configuration device ( 10 ) is arranged to be opposite the field device ( 30 ) and to authenticate the field device ( 30 ) to authenticate. Configuration device according to one of claims 1-10, characterized in that the cryptographic data are formed as a cryptographic key or as a one-time value. Field device ( 30 ), with: a random number generator ( 31 ) for generating a random number for generating cryptographic data, a coupling unit ( 32 ) for coupling the field device ( 30 ) with a configuration device ( 10 ) for configuring the field device ( 30 ) via an automation network ( 20 ), and an initialization unit ( 33 ) for initializing the random number generator ( 31 ) by means of one of the configuration device ( 10 ) and via the coupling unit ( 32 ) received start value (SW). System comprising: a number of field devices ( 30 ) according to claim 12, and a configuration device ( 10 ) for configuring the number of field devices ( 30 ) according to any one of claims 1-11. Method for configuring a number by means of an automation network ( 20 ) Coupling field devices ( 30 ), whereby the respective field device ( 30 ) a random number generator ( 31 ) for generating a random number (ZZ) for generating cryptographic data, comprising the steps of: providing ( 601 ) of a starting value (SW) for initializing the random number generator ( 31 ) of the field device ( 30 ), Form ( 602 ) of configuration data (KD) from configured data (PD) and the provided start value (SW), and transmission ( 603 ) of the formed configuration data (KD) on the field device ( 30 ). Method according to claim 14, characterized in that the starting value (SW) is encrypted onto the field device ( 30 ) and / or the starting value (SW) via an authenticated and encrypted channel to the field device ( 30 ) is transmitted.

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