ECU Boot Hash Verification for Non-Volatile Memory Integrity

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Solution Overview

Problem

The process of boot loading from a non-volatile memory (NVM) to a read-only memory (ROM) or flash memory and from a random access memory (RAM) to a processing unit in electronic control units (ECUs) lacks safety integrity, leading to potential data corruption during data transfer and storage, which is critical in automated driving applications.

Innovation Solution

A method involving cryptographic hash functions and hardware security modules is employed to determine and compare hash values before and after data transfer, ensuring data integrity by checking for any corruption, and utilizing error correction codes and encryption to maintain data accuracy and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is transferred from non-volatile memory to processing units during boot loading, then the system becomes operational, but data corruption may occur due to lack of safety integrity

Engineering Contradiction:
Improvedata integrityVSAvoidboot loading process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by calculating and storing hash values of data in non-volatile memory before the boot loading process. During boot loading, the stored hash values are retrieved and compared with newly calculated hash values to verify data integrity, preventing corruption without adding complex real-time checking mechanisms to the boot process itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces hash values as an intermediary element that mediates between the data stored in non-volatile memory and the processing units. This intermediary allows verification of data integrity during transfer without requiring complex error correction codes or redundant data storage, thus maintaining simplicity while ensuring reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If hash value comparison is performed during boot loading, then data integrity is verified, but processing time increases

Engineering Contradiction:
Improvedata integrity verificationVSAvoidboot loading time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs the time-consuming hash value calculation and storage operation in advance, during data writing to non-volatile memory, rather than during boot loading. This preliminary action ensures that during boot loading, only lightweight hash value retrieval and comparison operations are needed, minimizing the time added to the boot process while maintaining comprehensive integrity verification.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If safety integrity measures are implemented in boot loading, then ASIL compliance is achieved, but manufacturing complexity increases

Engineering Contradiction:
ImproveASIL integrity complianceVSAvoidECU manufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements self-service by having the electronic control unit automatically perform integrity verification using stored hash values during boot loading, without requiring external verification equipment or complex manufacturing processes. The ECU autonomously compares hash values and can detect corruption, simplifying manufacturing while achieving ASIL compliance through built-in safety mechanisms.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4198788B1Method and device for checking an integrity of data stored in a non-volatile memory of an electronic control unit of an vehicle
Publication Date: 2026.02.18 BAYERISCHE MOTOREN WERKE AG
  • EP4198788B1 patent drawingFigure 1
  • EP4198788B1 patent drawingFigure 2

AI summary

Provided is a method for checking an integrity of data stored in an electronic control unit of a vehicle, wherein the method comprises determining a first hash value based on the stored data using a hash function at the electronic control unit triggered by a request of a boot loader of the electronic control unit; determining a second hash value based on the stored data using the hash function at the electronic control unit triggered by a request of an external computing device connected to the electronic control unit; and checking the integrity of the stored data by comparing the determined first hash value to the determined second hash value.