Vehicle Control Unit Software Update via Segmented Cryptographic Verification
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Solution Overview
Problem
Existing methods for updating software in vehicle control units are either unsuitable for partial updates or require excessive computing power for cryptographic operations, making them inefficient and insecure.
Innovation Solution
A method that processes individual data blocks of the software using cryptographic functions, generating and verifying cryptographic material for each block, reducing the need for repeated cryptographic operations and enhancing security through a test data block that stores and updates only current cryptographic material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryptographic operations are performed for each data block during software updates, then security and authenticity verification are improved, but computing power requirements and processing time increase excessively
Solution Approach 1:
The software is divided into individual data blocks that can be updated independently. Each data block has its own cryptographic material (hash value) stored in the test data block, allowing selective updating and verification of only the modified blocks rather than processing the entire software suite.
Solution Approach 2:
Cryptographic material (hash values) for all data blocks is pre-calculated and stored in the test data block before the update process. When a data block is updated, its new hash value is pre-calculated and stored in the test data block, replacing the old hash value. This preliminary preparation eliminates the need for repeated cryptographic operations during verification.
2Reliability
If complete software updates are performed, then security is maintained, but update time and processing resources are excessively consumed
Solution Approach 1:
The software update process is segmented into individual data block updates. The control unit can identify which specific data blocks need updating and process only those blocks, rather than performing a complete software update. This segmentation enables partial updates that maintain security while significantly reducing update time and resource consumption.
Solution Approach 2:
Instead of performing complete software updates, the system performs partial updates by updating only the specific data blocks that have changed. The test data block stores cryptographic material for all data blocks, enabling verification of only the updated portions while maintaining overall software integrity and security.
3Measurement precision
If cryptographic material is stored for all data blocks, then verification accuracy is improved, but memory usage increases
Solution Approach 1:
The cryptographic material is organized in a segmented manner within the test data block, with each data block having its own hash value. This structured segmentation allows efficient storage and retrieval of cryptographic material for individual data blocks without requiring excessive memory resources.
Solution Approach 2:
Instead of storing complete software copies or redundant cryptographic information, the system uses hash values (cryptographic material) that are compact representations of each data block. These hash values provide accurate verification capability while occupying minimal memory space compared to storing full software images or redundant cryptographic data.
Data Source
AI summary
A method for updating software of a control unit of a vehicle which includes exchanging individual data blocks of the software in a memory of the control unit and generating cryptographic material for each exchanged data block by processing each exchanged data block with a cryptographic function. The method includes storing the generated cryptographic material in a test data block which contains cryptographic material for each data block and includes verifying the consistency of the cryptographic material, stored in the test data block, of all data blocks of the software by matching the cryptographic material stored in the test data block with consistency test data. The disclosed embodiments reduce the necessary cryptographic operations during a partial updating of the software of a control unit of a vehicle.