CAN Controller Filter Unit for Message Authentication
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Solution Overview
Problem
The CAN communication protocol is vulnerable to hacking attacks due to its broadcast nature and lack of message authentication, which can lead to spoofing and service denial attacks, compromising the security of critical vehicle systems.
Innovation Solution
A CAN controller with a transmission filter unit and reception filter unit that only allow messages with valid transmission IDs and check the transmission period to block or warn messages that do not match, using a protection memory to store filter values and a filter value setting unit to manage these filters, ensuring secure communication by preventing malicious messages from being transmitted or received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CAN communication uses broadcast method with message identifier for arbitration, then communication efficiency and simplicity are improved, but security vulnerability increases due to lack of authentication
Solution Approach 1:
The patent applies preliminary action by pre-storing valid message identifiers and transmission periods in a protection memory before communication occurs. The filter unit uses these pre-stored values to authenticate incoming messages, preventing spoofing attacks without adding complex real-time authentication protocols that would reduce communication efficiency.
Solution Approach 2:
The patent introduces an intermediary filter unit that sits between the CAN bus and the control unit. This filter unit mediates message transmission by checking identifiers and transmission periods against pre-stored valid values, blocking malicious messages while allowing legitimate communications to pass through unchanged.
2Adaptability or versatility
If filter values are stored in writable memory for flexibility, then adaptability is improved, but security decreases due to potential modification by attackers
Solution Approach 1:
The patent segments the memory system into two distinct parts: a protection memory that stores filter values in a read-only manner to ensure integrity, and a writable memory that can store temporary configurations. This segmentation allows the system to maintain both security (through protected filter values) and adaptability (through configurable parameters).
Solution Approach 2:
The patent applies local quality by making specific regions of the memory system have different accessibility properties. The protection memory region is configured to be readable but not writable by normal operations, while other memory regions maintain full read-write capability. This localized restriction ensures that critical filter values cannot be modified even if other parts of the system are compromised.
3Reliability
If transmission period checking is implemented to block malicious messages, then security is improved, but communication delay increases due to additional validation
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing valid transmission periods for each message identifier in the protection memory before communication begins. During runtime, the filter unit simply compares incoming message timing against these pre-stored values using simple arithmetic operations, avoiding complex real-time analysis that would cause significant delays.
Solution Approach 2:
The filter unit performs self-service by autonomously checking transmission periods against pre-stored valid values and automatically blocking messages that don't conform. This self-contained validation mechanism operates independently without requiring external intervention or complex processing, minimizing added latency while maintaining security.
Data Source
AI summary
A CAN controller safe against a CAN-communication-based hacking attack includes each CAN controller that filters a message to be transmitted to a CAN bus. A corresponding CAN controller filters only a message having a valid transmission ID to be transmitted. The CAN controller safe includes a transmission buffer, a transmission filter unit, a protection memory and a filter value setting unit. The transmission buffer unit temporarily stores transmission data to be transmitted to a CAN bus. The transmission filter unit has message IDs allowed to be transmitted as a transmission filter, configured to search for a message ID of the transmission data in the transmission filter, and filter the transmission data. The protection memory stores one or more filter values of the transmission filter and the filter value setting unit is configured to fetch the filter value stored in the protection memory.