# US 10,798,085 B2 · Updating of a digital device certificate of an automation device

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- Number: US 10,798,085 B2
- Document ID: US10798085B2
- Status: Granted
- Kind: B2
- Application number: 14/778,597
- Filed: 2014-03-04
- Published: 2016-02-25
- Granted: 2020-10-06
- Earliest claimed: 2013-03-21
- Assignees: Siemens Aktiengesellschaft
- Applicants: Siemens Aktiengesellschaft
- Inventors: Rainer Falk; Steffen Fries
- Web page: https://patentgrep.com/patent/US10798085B2

## CPC

- H04L 63/0823: {using certificates (cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263)}
- G05B 19/0428: {Safety, monitoring (G05B19/0423 takes precedence)}
- G06F 21/335: {for accessing specific resources, e.g. using Kerberos tickets}
- G06F 21/44: Program or device authentication
- G06F 21/572: {Secure firmware programming, e.g. of basic input output system [BIOS]}
- G06F 21/64: Protecting data integrity, e.g. using checksums, certificates or signatures
- H04L 9/3268: {using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]}
- H04L 63/061: {for key exchange, e.g. in peer-to-peer networks (cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838)}
- G05B 2219/24163: Authentication tag in configuration file
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

The invention relates to an automation device (41, 81), a system and a method for updating a digital device certificate (55, 86, 96) of an automation device (41, 81) of an automation system, wherein the automation device (41, 81) is authenticated to an authentication partner by means of at least one device certificate (55, 86, 96). The device certificate (55, 86, 96) is connected to device-specific configuration data of the automation device (41, 81). Following a modification of the configuration of the automation device (41, 81), according to the invention an updated device certificate (55, 86, 96) having device-specific configuration data according to the modified configuration of the automation device (41, 81) is determined by the automation device (41, 81) and subsequently used for authentication.

## Claims

### Claim 1

A method for updating a digital device certificate of an automation device in an automation system, the method comprising:
authenticating the automation device with respect to an authentication partner using at least one device certificate, the at least one device certificate being associated with device-specific configuration data relating to the automation device, the authenticating comprising automatically determining, by the automation device, in the event of or after a change in a configuration of the automation device, an updated device certificate having device-specific configuration data corresponding to the changed configuration of the automation device, and using the updated device certificate for authentication,
wherein the automation device comprises a plurality of predefined device certificates for determining the updated device certificate, the plurality of predefined device certificates having different device-specific configuration data corresponding to a respective plurality of changed configurations of the automation device, the plurality of predefined device certificates being predefined and stored on the automation device prior to any change in the configuration of the automation device, wherein determining the updated device certificate comprises selecting a device certificate having device-specific configuration data corresponding to the changed configuration of the automation device from the plurality of predefined device certificates having different device-specific configuration data.

### Claim 2 (depends on 1)

The method of claim 1, wherein the automation device comprises an integrated issuing unit, and
wherein determining the updated device certificate having device-specific configuration data corresponding to the changed configuration of the automation device comprises issuing, by the integrated issuing unit, the updated device certificate having device-specific configuration data corresponding to the changed configuration of the automation device.

### Claim 3 (depends on 2)

The method of claim 2, wherein the updated device certificate is issuable in any desired operating mode.

### Claim 4 (depends on 2)

The method of claim 2, wherein the updated device certificate is only issuable in a manner coupled to a particular operating mode.

### Claim 5 (depends on 2)

The method of claim 2, wherein the issuing unit is operable to issue device certificates for only the automation device in which the integrated issuing unit is included.

### Claim 6 (depends on 5)

The method of claim 5, further comprising allocating, by the integrated issuing unit, at least one identical parameter for each device certificate issued by the integrated issuing unit.

### Claim 7 (depends on 2)

The method of claim 2, further comprising:
creating, by the automation device, an item of attestation information for confirming the changed device-specific configuration data; and
transmitting the item of attestation information to the integrated issuing unit.

### Claim 8 (depends on 1)

The method of claim 1, wherein the determining comprises requesting, by the automation device, in the event of a change in the configuration of the automation device, a device certificate having device-specific configuration data corresponding to the changed configuration of the automation device from an issuing unit that is not included in the automation device.

### Claim 9 (depends on 1)

The method of claim 1, wherein a request message for requesting a device certificate having device-specific configuration data corresponding to the changed configuration of the automation device is protected by a digital signature by a generic, non-configuration-specific device certificate, a digital signature by a previous device certificate corresponding to the configuration used before the change in the configuration of the automation device, a device password, or any combination thereof.

### Claim 10 (depends on 1)

The method of claim 1, further comprising revoking the device certificate used before the change in the configuration of the automation device after the updated device certificate having changed device-specific configuration data has been determined.

### Claim 11 (depends on 1)

The method of claim 1, wherein the device certificate used before the change in the configuration of the automation device is still useable for a predefined time at least for a subset of authentication partners or for at least one subset of intended purposes for positive authentication after the updated device certificate having changed device-specific configuration data has been determined.

### Claim 12 (depends on 1)

The method of claim 1, wherein the plurality of device certificates or the updated device certificates issued in the event of a change in the configuration of the automation device have a different device key or a different device key pair in each case.

### Claim 13 (depends on 1)

The method of claim 1, wherein the plurality of device certificates or the updated device certificates issued in the event of a change in the device configuration each have the same device key or the same device key pair.

### Claim 14 (depends on 1)

The method of claim 1, wherein a regular operating mode of the automation device is activated only when an updated device certificate corresponding to the changed configuration of the automation device is available to the automation device.

### Claim 15 (depends on 1)

The method of claim 1, wherein the device certificate corresponding to an unchanged configuration is usable for a predefined time for positive authentication after a change in the configuration of the automation device.

### Claim 16

An automation device in an automation system for updating a digital device certificate, the automation device comprising:
at least one device certificate; and
a computing unit configured to access a program memory,
wherein device-specific configuration data and the at least one device certificate are stored in the program memory,
wherein the automation device is authenticated with respect to an authentication partner using a device certificate associated with device-specific configuration data relating to the automation device,
wherein the automation device is configured such that the automation device, in the event of or after a change in the configuration of the automation device, automatically accesses an updated device certificate having device-specific configuration data corresponding to the changed configuration of the automation device and then uses the updated device certificate having device-specific configuration data corresponding to the changed configuration of the automation device for authentication, and
wherein the automatic access of the updated device certificate comprises access, by the automation device, of the updated device certificate from a plurality of predefined device certificates having different device-specific configuration data corresponding to a respective plurality of changed configurations of the automation device, the plurality of predefined device certificates being predefined and stored on the automation device prior to any change in the configuration of the automation device.

### Claim 17 (depends on 16)

The automation device of claim 16, wherein an issuing unit is integrated in the automation device, and an issuing unit and a control unit, for controlling operation of the automation device, are included on a separate memory unit in each case, the separate memory units being connected by a separation unit.

### Claim 18

A system for updating a digital device certificate of an automation device in an automation system, the system comprising:
at least one automation device and at least one issuing unit, the at least one automation device having at least one device certificate and being authenticated with respect to an authentication partner using the at least one device certificate, which is associated with device-specific configuration data relating to the at least one automation device, the at least one automation device being configured such that the at least one automation device, in the event of a change in the configuration of the at least one automation device, automatically determines an updated device certificate having device-specific configuration data corresponding to the changed configuration of the at least one automation device and then uses the updated device certificate having device-specific configuration data corresponding to the changed configuration of the at least one automation device for authentication,
wherein the at least one issuing unit is configured to issue the updated device certificate having device-specific configuration data corresponding to the changed configuration of the at least one automation device, and
wherein the automatic determination of the updated device certificate comprises selection, by the at least one automation device, of the updated device certificate from a plurality of predefined device certificates having different device-specific configuration data corresponding to a respective plurality of changed configurations of the at least one automation device, the plurality of predefined device certificates being predefined and stored on the at least one automation device prior to any change in the configuration of the at least one automation device.
