Secure Channel Multiplexing for Low-Latency In-Vehicle Networks
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Solution Overview
Problem
Conventional communication protocols for automotive in-vehicle networks face challenges in managing secure channel communications due to high memory footprint, increased costs, and complexity, particularly in real-time control systems where key agreement messages introduce latency and safety risks.
Innovation Solution
Implement a system that uses locally stored key counter values to eliminate the need for dedicated key agreement messages and enables secure channel multiplexing, allowing nodes to generate session keys on-the-fly, reducing memory requirements and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated key agreement messages are used for secure channel communications, then security is maintained, but latency increases and real-time control is compromised
Solution Approach 1:
Key counters are pre-synchronized during system initialization or boot-up phase, so that when secure communications need to occur, both nodes already have matching key counter values. This preliminary action eliminates the need for time-critical key agreement messages during real-time operations, resolving the contradiction between maintaining security and avoiding latency.
2Adaptability or versatility
If multiple secure channel specific pre-shared session keys are stored for each node, then secure communications across multiple channels are supported, but memory footprint and cost increase
Solution Approach 1:
A single shared secret key is used universally across all secure channels, combined with channel-specific identifiers (SCI) to derive different session keys dynamically. This universal approach allows one key to serve multiple functions and channels, eliminating the need to store separate pre-shared keys for each channel, thus reducing memory footprint while maintaining support for multiple secure channels.
Solution Approach 2:
Instead of storing static pre-shared session keys for each channel, the system dynamically generates session keys at runtime by combining a shared secret key with channel identifiers. This dynamic key generation reduces memory requirements while maintaining the ability to support multiple secure channels with different security requirements.
3Reliability
If pre-shared long-term keys and secure channel specific pre-shared session keys are stored at each node, then secure communications are enabled, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the need for storing multiple pre-shared session keys from each node. Instead, only a single shared secret key is stored locally, while other key material is derived or exchanged through the communication protocol itself, simplifying the key management structure and reducing device complexity.
Solution Approach 2:
Nodes automatically derive their own session keys and authentication material using the shared secret key and their own identifiers through cryptographic functions. This self-service approach eliminates the need for manual key distribution and storage of multiple pre-shared keys, reducing both complexity and potential error sources in key management.
Data Source
AI summary
The described techniques address issues related to compatibility and cost-effectiveness of in-vehicle networks. The described techniques may utilize security protocols such as MACsec, for example, without the need to exchange separate key agreement messages and, consequently, meet the stringent starting time requirements for real-time control systems. Additionally, the described techniques may implement a secure channel multiplexing scheme that utilizes a session key management system to enable the use of a single secure channel at the endpoint (e.g. at each transmitting and receiving node) while supporting the implementation of multiple secure channels within a real-time control system. This advantageously allows for a significant reduction in the memory required by each node to store copies of session keys for each secure channel, as only a single session key needs to be stored locally by each node per secure channel.