Tampering Detection in Vehicle ECU Using CVN Logging

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Solution Overview

Problem

Unauthorized software installations in electronic control units of vehicles can lead to premature component wear and failure, making it difficult for manufacturers to detect and prove non-approved software usage, which compromises warranty commitments.

Innovation Solution

A method involving the calculation and logging of Checksum Verification Numbers (CVN) each time the engine is started, comparing them with stored values, and using a FIFO principle to manage a list of CVN entries, allowing for detection of unauthorized software use and tracing changes within the software application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hash function is applied periodically during vehicle operation to detect software tampering, then software tampering detection capability is improved, but detection complexity and computational overhead increase

Engineering Contradiction:
Improvesoftware tampering detection capabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores hash values of software regions during authorized installation before vehicle operation. This preliminary action eliminates the need for complex real-time hash calculations during vehicle operation, reducing computational overhead while maintaining detection capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the essential detection function by storing pre-calculated hash values and comparing them with current state, rather than implementing full periodic hash calculation systems. This extraction simplifies the detection mechanism while preserving tampering detection reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If multiple CVN storage positions are used to log software version changes, then ability to detect unauthorized software becomes more robust, but memory usage and system complexity increase

Engineering Contradiction:
Improveunauthorized software detection robustnessVSAvoidmemory storage requirements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system pre-allocates a fixed number of CVN storage positions (at least 10) during system initialization. This preliminary allocation optimizes memory usage by reserving only the necessary storage capacity needed for detecting unauthorized software, avoiding excessive memory consumption while ensuring detection robustness.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If CVN calculation is restricted to maximum one time per day, then difficulty of erasing unauthorized software traces increases, but detection response time decreases

Engineering Contradiction:
Improveunauthorized software trace persistenceVSAvoiddetection response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements periodic CVN calculation with a maximum frequency of once per day. This periodic action creates a time-based detection mechanism that persists unauthorized software traces for extended periods (days or weeks), making erasure difficult while maintaining practical detection capabilities through regular monitoring intervals.

Inventive Principle:
Principle #19Periodic action

4Measurement precision

If separate CVN lists are provided for different predefined parts of software application, then accuracy of detecting software changes improves, but system complexity and data management overhead increase

Engineering Contradiction:
Improvesoftware change detection accuracyVSAvoidCVN list management complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the software application into different predefined parts, each with its own separate CVN list. This segmentation enables precise detection of changes in specific software modules while maintaining manageable complexity through organized, modular data structures that can be independently monitored and updated.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2471020B1Tampering detection method
Publication Date: 2019.10.02 VOLVO TRUCK CORP
  • EP2471020B1 patent drawingFigure 1
  • EP2471020B1 patent drawingFigure 2~3

AI summary

The present invention relates to a method for detecting use of unauthorized software in an engine control unit provided in a vehicle, said method comprising the steps of: calculating CVN each time the engine is started, comparing a last calculated CVN with a last stored CVN in a list of a plurality of CVN entries, storing said last calculated CVN if said last calculated CVN is different to the last stored CVN together with a date of an entry in said list of CVN and/or the current odometer status, removing entries in the list of CVN according to FIFO principle when said list of CVN is full, and to present this upon request from an on-board or off-board tool.