ECU Authentication with Unique MAC Keys
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Solution Overview
Problem
Existing authentication systems for electronic control units in vehicles face challenges in securely authenticating individual ECUs when a common key is leaked, making it difficult to identify the leakage source and risking unauthenticated access.
Innovation Solution
The proposed authentication system uses a unique MAC key for each ECU, stored in a Hardware Security Module, to generate and verify authentication codes, allowing for secure identification and authentication between ECUs and a server device, even if the MAC key is leaked.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a common key is used for authentication among multiple ECUs, then the authentication process is simplified, but the security deteriorates because the leakage source cannot be identified and unauthenticated access becomes possible
Solution Approach 1:
The patent divides the single common key into multiple individual keys, with each ECU having its own unique key stored in its storage unit. This segmentation allows the system to maintain simplified authentication procedures while improving security by enabling identification of leakage sources and preventing unauthorized access using leaked keys.
2Reliability
If individual keys are assigned to each ECU, then security improves by enabling leakage source identification, but the system complexity increases
Solution Approach 1:
The server device performs multiple functions: it stores individual keys for all ECUs, receives authentication requests, retrieves the appropriate key based on ECU identification information, and verifies authentication codes. This multi-functionality consolidates key management complexity into a single centralized system rather than distributing it across multiple devices.
Solution Approach 2:
The server device acts as an intermediary between ECUs and the key management system. It receives authentication requests from ECUs, retrieves the corresponding individual keys from its storage unit, and performs verification. This intermediary approach centralizes key management complexity in a dedicated server rather than requiring each ECU to manage its own key securely.
3Ease of operation
If authentication data is transmitted without encryption, then the communication process is simplified, but the security deteriorates allowing unauthenticated access
Solution Approach 1:
The system performs preliminary authentication before allowing any data exchange between ECUs and the server. Each ECU must first transmit its identification information and authentication code through the encryption process established in the authentication phase. This preliminary authentication action ensures that only authenticated ECUs can subsequently access services, preventing unauthenticated access while maintaining simplified communication procedures for authorized devices.
Data Source
AI summary
An authentication system includes: ECUs constituting on-vehicle network and server device communicating with the ECU. The ECU stores ID and encryption key set individually to the ECU and used for authenticating data exchanged between the ECUs. The server device stores the ID and encryption key of the ECU. The ECU includes: first CPU configured to perform: generating authentication data; generating authentication code by encrypting the authentication data using the encryption key; and transmitting the ID, authentication data, and authentication code to the server device. The server device includes: second CPU configured to perform: acquiring the ID transmitted from the ECU; retrieving the encryption key of ECU corresponding to the ID acquired; acquiring the authentication data and authentication code transmitted from the ECU; and authenticating the ECU using the encryption key retrieved.