Centralized TRNG Aggregates Vehicle Entropy to Reduce ECU Cost
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Solution Overview
Problem
Vehicle-based control units face challenges in generating cryptographically secure random numbers quickly and cost-effectively, particularly due to difficulties in collecting sufficient entropy in deterministic systems like microcontrollers, which are crucial for secure communication and key exchange protocols.
Innovation Solution
A centralized random number generator system within a vehicle network that aggregates and processes entropy from various sources, including sensor measurement inaccuracies and cryptographic calculations, to generate and securely store random numbers, eliminating the need for individual random number generators in control units and simplifying entropy source additions or changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If true random number generators are installed in each control unit to provide secure random numbers quickly, then the availability of random numbers improves, but the cost of each ECU increases
Solution Approach 1:
The patent merges the random number generation functionality from individual distributed TRNGs in each control unit into a single centralized TRNG. This centralized generator collects entropy from multiple sources across the vehicle network and generates random numbers that are distributed to all control units, thereby reducing per-ECU costs while maintaining security and availability.
Solution Approach 2:
The centralized random number generator serves multiple control units simultaneously, providing a universal service across the entire vehicle network. This multi-functional approach allows a single TRNG to fulfill the random number generation needs of numerous ECUs, eliminating the need for each ECU to have its own dedicated generator.
2Reliability
If true random number generators are installed in each control unit to ensure cryptographic security, then the security quality improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple distributed random number generation functions into a single centralized TRNG, reducing the total number of generators from many individual units to one central unit. This consolidation maintains cryptographic security through centralized entropy collection and processing while significantly reducing overall system complexity.
3Reliability
If entropy is collected from multiple sources in a centralized system, then the entropy quality improves, but the time to collect sufficient entropy increases
Solution Approach 1:
The system performs preliminary entropy collection and aggregation during vehicle startup and operation, building up a reservoir of high-quality entropy before random number generation is needed for cryptographic operations. This advance preparation ensures that when random numbers are required, sufficient entropy is already available, reducing latency.
Solution Approach 2:
The centralized TRNG continuously collects and aggregates entropy from multiple sources throughout vehicle operation, maintaining a continuous supply of high-quality random data. This ongoing entropy collection process ensures that entropy quality improves over time while the system remains ready to provide random numbers on demand.
Data Source
AI summary
A method for providing random numbers for control units communicating via a vehicle network, in which a random number generator having an aggregation component, a storage unit and a distribution component is provided. A plurality of control units each with at least one entropy source are formed. Their raw data are transmitted to the aggregation component via the vehicle network. A quality assurance of the combined raw data from the entropy sources is carried out using only those combined raw data which both occur in a non-deterministic manner and contain a minimum degree of entropy as qualified raw data. The qualified raw data are converted into an aggregated data block by a cryptographic one-way function and securely stored as a random number in the storage unit. The random number stored in the storage unit is transmitted to a control unit via the vehicle network by the distribution component.