Checksum Verification for Simulation Model Integrity

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Solution Overview

Problem

Users face challenges in trusting the integrity of computer simulation model packages, particularly FMUs, as the performance of binary libraries within them may be unknown and potentially modified by malicious parties, leading to concerns about modifications.

Innovation Solution

A system and method that generate a computer simulation model package with a checksum mechanism, where a first checksum is derived and stored within a text file, and an instantiation function is generated to verify the model by comparing the stored checksum with a newly derived checksum upon instantiation, ensuring the model's integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a computer simulation model package is distributed from different sources, then model availability and versatility are improved, but model integrity and trustworthiness deteriorate due to potential malicious modifications

Engineering Contradiction:
Improvemodel availabilityVSAvoidmodel integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-computing and embedding a checksum (hash value) of the binary library into the model description text file before distribution. This preliminary verification mechanism is built into the FMU package structure, allowing any user to verify model integrity without needing to trust the source. The checksum is calculated in advance and stored alongside the model, enabling immediate verification upon receipt.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a checksum (hash value) as an intermediary element that mediates between the model creator and the model user. This intermediary provides a mathematical proof of integrity that bridges the trust gap when models are distributed from different sources. The checksum acts as a digital fingerprint that can be independently verified without requiring access to the original model or trust in the distributor.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If checksum verification is implemented in the simulation model package, then model integrity and trustworthiness are improved, but package complexity and processing overhead increase

Engineering Contradiction:
Improvemodel integrityVSAvoidpackage complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the checksum verification mechanism to work with any simulation tool that supports the FMI standard. The verification process is tool-agnostic and can be performed by any compliant simulator without requiring special modifications. This universal approach minimizes the practical complexity burden, as the same verification mechanism serves all FMI-based simulation tools.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service by making the verification process automatic and self-contained within the FMU package structure. The model description file contains all necessary verification information (checksum algorithm and value), allowing the system to self-verify without external intervention. The verification is performed automatically when the model is loaded, reducing manual overhead and complexity for users.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If checksum verification is performed during instantiation, then detection precision of modifications is improved, but processing time and computational overhead increase

Engineering Contradiction:
Improvedetection precisionVSAvoidinstantiation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing only a checksum comparison rather than a full re-verification of the entire binary library. The verification process computes a hash of the binary and compares it to the stored checksum, which is a relatively lightweight operation compared to full model validation. This partial verification approach provides sufficient detection precision for integrity checking while minimizing the time penalty during instantiation.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4361818A1Generation of a computer simulation package
Publication Date: 2024.05.01 SIEMENS AG
  • EP4361818A1 patent drawingFigure 1
  • EP4361818A1 patent drawingFigure 2~3
  • EP4361818A1 patent drawing

AI summary

The invention provides a system and computer-implemented method for generating a computer simulation model package for a computer simulation model of a technical system, as well as a computer-implemented method for verifying the computer simulation model. The computer simulation model package comprises a binary file or source code comprising a computer simulation model of the technical system, and a text file assigned to the computer simulation model. A first checksum of the at least one binary file or the source code is derived and stored in the text file. An instantiation function for verifying the computer simulation model is generated, wherein the instantiation function is run each time the computer simulation model is instantiated and wherein the instantiation function comprises the function steps: - deriving a second checksum from a binary file or source code stored in the computer simulation model package, - comparing the second checksum with the stored first checksum, - outputting a comparison result.