Constrained operation of a field device

A method for operating a key generation device, the method comprising:

• receiving a predefined operating constraint for operating a field device,
• generating a base key for the field device,
• transmitting the base key to the field device, and
• generating a key for a control device based on the predefined operating constraint, wherein the control device and the field device are configured to interact using the key and a further key generated at the field device based on the base key and a current constraint parameter relating to the predefined operating constraint, wherein the control device and the field device are configured to interact by communicating data using the generated further key, and wherein the further key is generated by dynamically modifying the base key with the current constraint parameter, and wherein the generated further key matches the key for the control device based on the predefined operating constraint,
• wherein, in response to a change to the field device related to the predefined operating constraint, the field device updates the generated further key so that the updated generated further key does not match the key for the control device, and as a function of the updating, the field device no longer interacts with the control device,
• wherein the predefined operating constraint defines one or more constraints which must be fulfilled for operating the field device,
• wherein a predefined function is executed by the field device when the current constraint parameter fulfills the predefined operating constraint, and
• wherein the predefined function relates to a configuration and placing into operation of the field device issued by the control device.

A field device for interacting with a control device, the field device comprising a processor, a communication interface, and a logic configured to:

• receive, from a key generation device, a base key,
• determine a current constraint parameter relating to a predefined operating constraint for operating the field device,
• generate a further key based on the base key and the current constraint parameter, wherein the further key is generated by dynamically modifying the base key with the current constraint parameter,
• interact with the control device using the generated further key, wherein data communicated when the field device interacts with the control device uses the generated further key, and wherein the generated further key matches a key for the control device generated based on the predefined operating constraint, and
• in response to a change to the field device related to the predefined operating constraint, updating, by the field device, the generated further key so that the updated generated further key does not match the key for the control device, and as a function of the updating, the field device no longer interacts with the control device,
• wherein the predefined operating constraint defines one or more constraints which must be fulfilled for operating the field device,
• wherein a predefined function is executed by the field device when the current constraint parameter fulfills the predefined operating constraint, and
• wherein the predefined function relates to a configuration and placing into operation of the field device issued by the control device.

A key generation device, comprising a processor, a communication interface, and a logic configured to:

• receive a predefined operating constraint for operating a field device,
• generate a base key for the field device,
• transmit the base key to the field device, and
• generate a key for a control device based on the predefined operating constraint, wherein the control device and the field device are configured to interact using the key and a further key generated at the field device based on the base key and a current constraint parameter relating to the predefined operating constraint, wherein the control device and the field device are configured to interact by communicating data using the key and the further key generated at the field device based on the base key and the current constraint parameter, wherein the further key is generated by dynamically modifying the base key with the current constraint parameter, and wherein the generated further key matches the key for the control device based on the predefined operating constraint,
• wherein, in response to a change to the field device related to the predefined operating constraint, the field device updates the generated further key so that the updated generated further key does not match the key for the control device, and as a function of the updating, the field device no longer interacts with the control device,
• wherein the predefined operating constraint defines one or more constraints which must be fulfilled for operating the field device, wherein a predefined function is executed by the field device when the current constraint parameter fulfills the predefined operating constraint, and
• wherein the predefined function relates to a configuration and placing into operation of the field device issued by the control device.