In-Vehicle ECU Key Sharing With MGAL-Based MAC Authorization
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Solution Overview
Problem
The increasing number of Electronic Control Units (ECUs) in modern vehicles leads to higher costs and complexity in maintaining security, as each ECU typically requires its own transmit key to prevent spoofing.
Innovation Solution
Implementing a single shared secret key among all virtual ECUs (V-ECUs) within a node, with a security peripheral that uses a MAC Generate Allow List (MGAL) to authorize message transmission and generate message authentication codes (MACs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each ECU is provided with a separate transmit key to ensure security, then security is improved, but the cost and complexity increase due to the need to accommodate increasing numbers of ECUs
Solution Approach 1:
The patent merges the security functions of multiple ECUs into a single security peripheral within one ECU node. Instead of each ECU having its own separate key storage and security management, multiple virtual ECUs share a common security peripheral that contains a single transmit key and MAC generation capability. This consolidation reduces key management complexity while maintaining security through centralized authorization control via the MGAL.
2Reliability
If each ECU is provided with a separate transmit key to prevent spoofing, then security is improved, but the number of required key slots increases leading to higher costs
Solution Approach 1:
The security peripheral is designed as a universal security mechanism that serves multiple virtual ECUs simultaneously. A single transmit key stored in the security peripheral is used to generate MACs for messages from multiple different V-ECUs, identified through the MGAL authorization list. This multi-functional approach eliminates the need for separate key slots for each ECU, reducing the quantity of key storage resources required while maintaining the ability to authenticate messages from multiple sources.
3Device complexity
If a single shared key is used among multiple V-ECUs, then the number of key slots is reduced, but the need for access request inspections increases to maintain security
Solution Approach 1:
The MGAL (MAC Generate Allow List) is pre-configured with authorization information before runtime operations. This preliminary setup includes pre-defining which virtual ECUs are authorized to use the shared transmit key for MAC generation. By performing this authorization configuration in advance, the system avoids the need for complex runtime access request inspections, as the security peripheral can quickly determine authorization status by checking the pre-loaded MGAL, thus maintaining message transmission efficiency.
Data Source
AI summary
An electronic control unit (ECU), or node, is configured to use a single key for all virtual ECUs (V-ECUs) having a message to transmit. The ECU also may include a security peripheral that includes the stored shared key. The security peripheral may further include a policy enabling it to detect if a request from the V-ECU is valid, in which case it generates a MAC. The security peripheral is also used to store information in a MAC Generate Allow List (MGAL), which may define the policy about when the V-ECU can transmit. The ECU may include a crypto-engine, which stores shared keys from other nodes used to verify MACs transmitted by other nodes.