Secure Channel Multiplexing With Embedded Key Counters
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Solution Overview
Problem
Conventional communication protocols in automotive in-vehicle networks face challenges with increased memory footprint, cost, and complexity due to the need for pre-shared long-term keys and session keys, leading to latency issues in key agreement processes that are unsuitable for real-time control systems.
Innovation Solution
Implementing a system where nodes store locally a group-wide key counter value, eliminating the need for dedicated key agreement messages by including a representation of this counter in each secured message, allowing nodes to synchronize and generate session keys on-the-fly, thus enabling secure channel multiplexing with reduced memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional communication protocols use pre-shared long-term keys and session keys for secure communications, then security authentication and encryption are ensured, but memory footprint and device complexity increase significantly
Solution Approach 1:
The patent extracts the key agreement process from dedicated key agreement messages and integrates it into the data communication process itself. By including the key counter in the data message, the system eliminates separate key distribution overhead and reduces the memory footprint by removing the need for separate key storage mechanisms.
Solution Approach 2:
The data message serves multiple functions simultaneously: it carries both the actual data payload and the key counter for key derivation. This multi-functionality eliminates the need for separate key agreement messages and reduces overall system complexity while maintaining security authentication.
2Reliability
If dedicated key agreement messages are used to distribute shared session keys, then secure communications are established, but latency increases and real-time control is compromised
Solution Approach 1:
The patent merges the key agreement process with the data communication process. The key counter is included within the data message itself, allowing key derivation to occur simultaneously with data transmission. This eliminates the sequential latency of separate key agreement messages and enables real-time secure communication establishment.
Solution Approach 2:
The key counter is prepared and included in advance within the data message structure, allowing receiving nodes to immediately derive the session key without waiting for separate key agreement messages. This preliminary inclusion of key material enables instant secure communication establishment.
3Reliability
If multiple secure channels with separate pre-shared session keys are implemented, then message prioritization and timely delivery are ensured, but device complexity and memory requirements increase
Solution Approach 1:
The patent implements dynamic key derivation where session keys are generated on-demand based on the key counter value included in each message, rather than storing multiple static pre-shared session keys. This dynamic approach allows the system to maintain multiple secure channels with message prioritization capabilities while significantly reducing memory requirements.
Data Source
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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.