ECU MAC Segmentation for In-Vehicle Network Security
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Solution Overview
Problem
In existing in-vehicle network systems, the limited size of the data field in CAN frames restricts the storage and transmission of a secure message authentication code (MAC), making it difficult to ensure adequate safety, as a larger MAC size is necessary for greater security but cannot be accommodated within the 64-bit data field.
Innovation Solution
The electronic control unit divides the MAC into multiple partial MACs and stores them across multiple frames, along with identification information indicating their positions, allowing secure transmission regardless of the data field size, using a configuration that includes a MAC generation unit, division unit, identification information generation unit, frame generation unit, and transmission unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger MAC size is used to improve security, then security is improved, but the data field size limit of 64 bits cannot accommodate the MAC
Solution Approach 1:
The patent divides the MAC into multiple partial MACs that can be stored and transmitted separately across multiple frames. This segmentation allows the complete MAC to exceed the 64-bit data field limit while maintaining security, as the full MAC is reconstructed from multiple parts during verification.
2Quantity of substance
If the MAC is divided into multiple partial MACs and stored in multiple frames, then the MAC size can exceed 64 bits, but the device complexity increases
Solution Approach 1:
The patent introduces identification information as an intermediary element that links multiple partial MACs across different frames. This intermediary mechanism enables the system to manage the complexity of distributed MAC storage by providing a structured way to reference and reconstruct the complete MAC from its parts.
3Quantity of substance
If multiple frames are used to store the MAC, then the MAC can be larger than 64 bits, but the transmission time increases
Solution Approach 1:
The patent combines the transmission of transmission data and multiple partial MACs across multiple frames in a coordinated manner. By merging these elements into a unified multi-frame transmission structure with proper identification information, the system optimizes the transmission process to minimize the overall time penalty compared to transmitting a single large MAC in one frame.
Data Source
AI summary
An electronic control unit is configured to generate a MAC on a basis of transmission data, divide the MAC into a plurality of partial MACs, generate individual identification information items which are information items indicating respective portions of the MAC occupied by the individual partial MACs, store the transmission data in at least one of a plurality of frames and store the individual partial MACs and the individual identification information items corresponding thereto in the plurality of respective fames, and transmit the plurality of frames.