Secure Communications With Key Counters and Live Membership Tracking
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Solution Overview
Problem
Conventional communication protocols in automotive in-vehicle networks face significant latency and security risks due to the need for key agreement messages to distribute shared keys, which is unsuitable for real-time control systems.
Innovation Solution
Implementing a system that uses locally stored key counter values and live membership groups to synchronize session keys without separate key agreement messages, ensuring robust and secure communication by including counter values in each message and using challenge requests within existing message formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated key agreement messages are used to distribute shared keys, then security is improved, but latency increases and communication overhead increases
Solution Approach 1:
The patent combines key distribution with regular data messages by embedding encrypted key material within the payload of existing communication frames. This merging eliminates the need for separate dedicated key agreement messages, thereby reducing latency and communication overhead while maintaining security through the use of encryption and authentication mechanisms.
Solution Approach 2:
The system performs preliminary key establishment by pre-sharing public keys between nodes before actual communication begins. This preliminary action allows nodes to encrypt key update material using pre-established public keys, enabling secure key distribution without requiring separate key agreement protocols during runtime communication.
2Reliability
If dedicated key agreement messages are used to distribute shared keys, then security is improved, but device complexity increases
Solution Approach 1:
The patent makes regular data messages multi-functional by enabling them to simultaneously carry both data payload and encrypted key update material. This universality allows a single message type to serve multiple purposes, eliminating the need for separate dedicated key agreement message formats and reducing overall communication overhead and device complexity.
Solution Approach 2:
The system extracts the key distribution function from dedicated key agreement protocols and integrates it into regular data message flows. By taking out the separate key agreement mechanism and embedding key distribution capabilities within existing message structures, the system reduces communication overhead while maintaining security.
3Reliability
If key agreement messages are used for secure communication resumption, then security is maintained, but speed of resumption decreases
Solution Approach 1:
The system performs preliminary key establishment by pre-sharing public keys between nodes before communication resumption is needed. This preliminary action enables rapid key material exchange during resumption by using pre-established cryptographic pairs, allowing nodes to quickly encrypt and share fresh key material without undergoing lengthy key agreement protocols.
Solution Approach 2:
The system dynamically adapts key distribution mechanisms based on communication state. During normal operation and resumption scenarios, nodes use pre-shared public keys for rapid key material exchange, while maintaining the option to fall back to more formal key agreement protocols if security requirements demand, thus optimizing speed without compromising security.
Data Source
AI summary
The described techniques address issues to achieve key agreement without the need to exchange separate key agreement messages and, consequently, meets the stringent starting time requirements for real-time control systems. This is achieved using a group-wide key counter, with each node storing the latest value of this counter that was observed via the last received secured message. This counter value increases monotonically, and nodes maintain synchronization by transmitting this counter value (or a representation of the counter value) in each secured message. The use of key counters may be extended to guard against weak replay attacks via the implementation of a live membership tracking solution, which defines one or more membership groups. Each node within a membership group may request, or “challenge” other nodes with the same membership group at any time to verify their online status, and this online status may be maintained over time.