Vehicle Network Random Number Generation Using CMAC Entropy
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Solution Overview
Problem
Existing vehicle communication networks face security vulnerabilities due to the potential for repeat or guessable random numbers generated from noise sources, allowing unauthorized sources to compromise network security.
Innovation Solution
A system that monitors the vehicle communication network for eligible messages with high information entropy, selects and combines their cipher-based message authentication codes (CMACs) to seed a random number generator, ensuring unique and unpredictable seed values, thereby preventing unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seed value is selected from a source of noise in the system, then the likelihood of an unauthorized source guessing the seed value is reduced, but repeat values and predictable changes between successive seed values may occur
Solution Approach 1:
The patent introduces a cryptographic hash function as an intermediary between the noise source and the random number generator. The hash function processes the noisy data to produce a uniform distribution of output values, eliminating repeat values and predictability while preserving the entropy from the noise source. This mediator transforms the problematic raw noise into a reliable seeding input.
Solution Approach 2:
The patent changes the parameter distribution of the seed values by applying a cryptographic hash function. The hash function transforms the non-uniform, potentially repeating noise values into uniformly distributed values with high entropy, fundamentally changing the statistical properties of the seed values to eliminate predictability and repetition.
2Adaptability or versatility
If a random number generator is used for security applications, then security functions can be performed, but the system becomes vulnerable to unauthorized access if the seed value is guessable
Solution Approach 1:
The patent performs preliminary action by collecting and processing entropy from multiple noise sources before seeding the random number generator. The system continuously monitors and accumulates entropy from various vehicle system sources, processes this data through cryptographic hash functions, and maintains a secure entropy pool ready for random number generation, ensuring high-entropy seeds are always available before security operations begin.
Solution Approach 2:
The patent combines multiple different noise sources from the vehicle system into a composite entropy pool. By aggregating entropy from various independent sources (sensors, timers, counters, etc.) and processing them together through cryptographic hash functions, the system creates a composite seed value with higher overall entropy and unpredictability than any single source could provide.
Data Source
AI summary
An onboard communication network of a vehicle is monitored to detect a plurality of available messages that include respective cipher-based message authentication codes (CMAC) and that were identified as eligible messages based on having an information entropy greater than a specified threshold. A first message is selected from the plurality of available messages. The CMAC of the selected message is input into a random number generator that outputs a random number seeded by the CMAC of the selected message. Then the random number is provided.