Vehicle Network Security Using Time-Synchronized Symmetric Keys
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Solution Overview
Problem
Existing vehicle network security systems face challenges in efficiently and quickly deriving symmetric keys for secure data transmission, particularly due to computational load issues with asymmetric key exchange mechanisms and the vulnerability of key exchange processes over non-safe channels.
Innovation Solution
A vehicle network security system that generates symmetric keys using a time synchronization process, where a symmetric key generation unit creates keys synchronized with real-time data from hardware clocks in electronic control units, and these keys are stored and managed for efficient use in encryption and decryption sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asymmetric key exchange mechanism is used to safely exchange symmetric keys, then security is improved, but computation time increases
Solution Approach 1:
The system pre-generates multiple symmetric keys and stores them in a key pool before actual communication occurs. When communication is needed, a key is randomly selected from the pre-generated pool, eliminating the need for real-time asymmetric key exchange and reducing computation time while maintaining security.
Solution Approach 2:
Each ECU generates its own symmetric keys using its unique identifier and stored secret information, without requiring key distribution from a central authority or exchange with other ECUs. This self-service approach eliminates the computational overhead of asymmetric key exchange while ensuring each node has secure keys.
2Reliability
If asymmetric key exchange mechanism is used for safe key exchange, then security is improved, but computational load increases
Solution Approach 1:
Symmetric keys are generated and stored in advance in a key pool, so that during actual communication, no computationally intensive key exchange is needed. The system only performs lightweight random selection from the pre-generated keys, dramatically reducing computational load while maintaining security.
Solution Approach 2:
The system uses inexpensive symmetric keys that can be quickly generated and discarded, replacing the need for expensive asymmetric key operations. Each symmetric key is used for a specific communication session and then replaced, providing security without the high computational cost of asymmetric cryptography.
3Productivity
If symmetric keys are exchanged over non-safe channels, then communication efficiency is improved, but security vulnerability increases
Solution Approach 1:
Each ECU independently generates symmetric keys using its own unique identifier and pre-stored secret information, without requiring key exchange over communication channels. This eliminates the security vulnerability of transmitting keys over non-safe channels while maintaining the efficiency of symmetric key cryptography.
Solution Approach 2:
The patent extracts the key generation process from the communication channel itself, using only locally stored information (unique identifier and secret) to generate keys. This removes the vulnerable key exchange step from the system while preserving the benefits of efficient symmetric encryption.
4Loss of time
If additional procedures and salt values are shared for symmetric key derivation without asymmetric keys, then computation time is reduced, but system complexity and security management difficulty increase
Solution Approach 1:
The patent extracts and removes the complex salt value management and additional derivation procedures from the system. Instead, it uses a simplified approach where symmetric keys are directly generated from the unique identifier and pre-stored secret information, reducing system complexity while maintaining fast key generation.
Solution Approach 2:
Each ECU self-generates symmetric keys using only its unique identifier and pre-stored secret information, without requiring additional shared salt values or complex coordination procedures with other ECUs. This self-service mechanism simplifies the system architecture while enabling rapid key generation.
Data Source
AI summary
A vehicle network security system using symmetric keys derived based on time synchronization includes a symmetric key generation unit configured to generate a symmetric key shared by a transmission unit that transmits data and a reception unit that receives data, and store the symmetric key in a specific slot. The vehicle network security system also includes a symmetric key processing unit configured to call the symmetric key in the specific slot to transmit and receive data when an application software program creates an encryption or decryption session. The symmetric key is generated using a factor synchronized with time data transferred from a hardware clock (HC) included in electronic control units (ECUs) in a vehicle network.