CANbus ECU End-to-End Security via PUF Key Generation
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Solution Overview
Problem
Internet of Things (IoT) devices, particularly automotive Electronic Control Units (ECUs), are vulnerable to cyber-attacks due to lack of end-to-end communication security, leading to risks of spoofing and eavesdropping over shared communication networks like CANBus.
Innovation Solution
Implementing end-to-end communication security by generating symmetric keys using controller-specific features like physically unclonable functions (PUFs), which are used for encryption and authentication, ensuring only verified controllers can communicate securely over the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end-to-end communication security is implemented using symmetric keys and encryption, then communication security is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-distributing symmetric keys to controllers before they join the network. The key distribution server generates and stores symmetric keys in controllers during manufacturing or initialization, so that when controllers need to communicate securely, they already possess the necessary encryption keys without performing complex key exchange protocols at runtime.
Solution Approach 2:
The patent introduces a key distribution server as an intermediary that manages symmetric key distribution to controllers. This server acts as a trusted mediator that authenticates controllers and provides them with appropriate symmetric keys, simplifying the security architecture by centralizing key management rather than requiring direct peer-to-peer key exchange between all controllers.
2Loss of information
If encryption is performed for all communications between controllers, then confidentiality is improved, but processing time increases
Solution Approach 1:
The patent applies local quality by selectively encrypting only the data payload portion of CAN bus messages rather than encrypting entire message frames or all communication channels. This approach encrypts only the sensitive information fields while leaving message identifiers, headers, and non-sensitive data unencrypted, thereby reducing the amount of data requiring encryption processing.
Solution Approach 2:
The patent implements partial encryption by applying encryption only to specific critical data fields within messages rather than encrypting all message contents uniformly. The system identifies and encrypts only the portions of messages containing sensitive information (such as control commands or personal data) while leaving other fields in plaintext, achieving adequate security with reduced processing overhead.
3Reliability
If symmetric keys are distributed to all controllers, then authentication capability is improved, but security vulnerability increases
Solution Approach 1:
The patent applies local quality by assigning different symmetric keys to different controllers based on their specific roles, communication partners, and security requirements. Rather than giving all controllers the same key or universal access keys, each controller receives a tailored set of symmetric keys that are appropriate for its specific communication needs, limiting the scope of potential security breaches.
Solution Approach 2:
The patent segments the symmetric key distribution system by creating multiple isolated key pairs rather than using a single master key for all communications. Each controller has its own segmented key space, and keys are distributed on a need-to-know basis for specific communication channels. This segmentation ensures that if one key is compromised, the security of other communication channels remains intact.
Data Source
AI summary
In one implementation, a method for providing end-to-end communication security for a controller area network (CANbus) in an automotive vehicle across which a plurality of electronic control units (ECU) communicate is described. Such an automotive vehicle can include, for example, a car or truck with multiple different ECUs that are each configured to control various aspects of the vehicle's operation, such as an infotainment system, a navigation system, various engine control systems, and/or others.