Encrypted Technical System Control Using Homomorphic Processing

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Solution Overview

Problem

Current control systems for technical installations lack sufficient data security, particularly in distributed systems where computing power is limited, making them vulnerable to unauthorized access and requiring extensive encryption that is resource-intensive.

Innovation Solution

Implementing homomorphic encryption to enable encrypted data processing without decryption, allowing control commands to be generated and executed using public keys, reducing the need for computing power and ensuring secure access, even in insecure environments like cloud servers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If extensive data encryption is implemented in the control system, then data security is improved, but computing power demand increases significantly

Engineering Contradiction:
Improvedata securityVSAvoidcomputing power demand
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The system segments encryption operations between different devices: the input device performs encryption locally before transmission, the controller processes encrypted data without decryption, and only the device control device decrypts control commands. This distribution of cryptographic operations reduces the computing burden on any single device, particularly on resource-constrained PLCs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces encrypted model properties as an intermediary representation that allows the controller to process control logic without accessing plaintext data. The controller operates on encrypted inputs and encrypted model properties to generate encrypted control commands, eliminating the need for the controller to perform extensive decryption operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If data is encrypted and processed in distributed systems, then data security is improved, but device complexity increases

Engineering Contradiction:
Improvedata securityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides cryptographic functionality into discrete components: key pair generation at the device control device, encryption at the input device, and encrypted processing at the controller. Each device has a specific cryptographic role, reducing the complexity burden on individual components while maintaining overall system security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the state of data from plaintext to encrypted form at different stages of the control loop. Inputs are encrypted before transmission, model properties are stored in encrypted form, and control commands are encrypted during transmission. This parameter transformation allows secure distributed processing without requiring all devices to implement full cryptographic suites.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple users access the control system, then system versatility is improved, but vulnerability to unauthorized access increases

Engineering Contradiction:
Improvemulti-user access capabilityVSAvoidunauthorized access risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Encrypted model properties serve as an intermediary that allows the controller to facilitate multi-user access without exposing sensitive data. The controller processes encrypted inputs from multiple users and generates encrypted control commands without ever decrypting the data, preventing unauthorized access while maintaining system versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device control device performs self-service decryption of control commands using its private key, eliminating the need for the controller or other devices to decrypt sensitive data. This self-contained cryptographic approach allows multiple users to access the system through the controller without increasing vulnerability, as no intermediate device has access to plaintext data.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3667441B1Method and device for encrypted controlling of a technical system
Publication Date: 2021.10.06 ETM PROFESSIONAL CONTROL GMBH
  • EP3667441B1 patent drawingFigure 1~2

AI summary

Method for controlling a technical system, wherein an input device (10) acquires a device parameter (11, 12), encrypts it and transmits it as encrypted input data (21, 22) to a controller (20), and the controller (20) generates an encrypted control command (41-44) from the encrypted input data (21, 22) and a stored, encrypted model property (31) which describes the technical system (1) by means of at least one mapping function (5), without decrypting the encrypted input data (21, 22), and transmits it to a first device control device (50), and the first device control device (50) controls the technical system (1) by means of the at least one encrypted control command (41-44), wherein the input device (10), the controller (20) and the first device control device (50) use a method for generating a homomorphic encryption during the encryption process.