Ring Generator TRNG with Oscillator Injection and Self-Test

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Solution Overview

Problem

Existing hardware roots of trust face challenges in balancing security demands with functionality and testability, and pseudorandom number generators are vulnerable to cryptanalytic attacks.

Innovation Solution

A ring-generator-based true random number generator system is developed, utilizing inverter-based ring oscillators to inject bits into a ring generator, combined with blocking circuitry, hashing circuitry, and a controller to enhance security and testability, while ensuring randomness and ease of synthesis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pseudorandom number generators are used to generate random numbers, then a large number of non-repeated pattern sequences can be generated, but the sequences are deterministic and vulnerable to cryptanalytic attacks

Engineering Contradiction:

ImprovesecurityVSAvoiddeterminism vulnerability

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces deterministic mechanical/pattern-based number generation with stochastic physical phenomena. Specifically, it uses thermal noise, metastability, quantum effects, phase jitter, or glitch of digital circuits as physical random sources, substituting the deterministic pattern generation mechanism with physical stochastic processes that are inherently unpredictable and resistant to cryptanalytic attacks.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If existing hardware roots of trust are designed to meet security demands, then security functions are enhanced, but complexity and area overhead increase

Engineering Contradiction:

ImprovesecurityVSAvoidcomplexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the random number generation function as a separate, dedicated module within the hardware root of trust. By taking out the RNG function and implementing it using simple inverter-based ring oscillators rather than complex cryptographic modules, the design achieves security without requiring complex overall system architecture, thereby reducing device complexity and area overhead.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple, lightweight inverter-based ring oscillators that can be easily implemented in standard digital logic, replacing expensive and complex cryptographic hardware modules. These simple oscillator circuits are sufficient for generating secure random numbers when combined with proper seeding and output handling, providing security with minimal resource consumption.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If existing hardware roots of trust are designed to meet security demands, then security functions are enhanced, but testability and functionality are compromised

Engineering Contradiction:

ImprovesecurityVSAvoidtestability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements self-testing capabilities where the hardware root of trust can autonomously verify its own functionality and security properties. The ring oscillator-based RNG includes built-in test modes that allow the system to self-diagnose random number generation quality, detect faults, and validate security functions without requiring external testing equipment or complex test procedures, thereby maintaining testability while enhancing security.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides a lightweight, non-intrusive hardware root of trust with enhanced security, capable of generating truly random numbers resistant to attacks, and facilitating self-testing and secure data transformation.

Implementation Method 1

true random number generators can generate random numbers based on various stochastic characteristics, such as the thermal noise, metastability, quantum effects, phase jitter or glitch of digital circuits

Methodology Applied

Scientific EffectThermal noise:

Implementation Method 2

Methodology Applied

Scientific EffectMetastability: Metastability

Implementation Method 3

Methodology Applied

Scientific EffectQuantum effects:

Data Source

PatentUS20260023533A1Ring-generator-based true random number generator for hardware root of trust

Publication Date: 2026.01.22 SIEMENS INDUSTRY SOFTWARE INC

AI summary

A random number generator comprises a ring generator and one or more inverter-based ring oscillators. The one or more inverter-based ring oscillators is configured to inject bits into the ring generator at a plurality of location. If there is more than one inverter-based ring oscillators, the inverter-based ring oscillators may have different numbers of inverting elements and may inject bits into the ring generator at different locations. At least one of the one or more inverterbased ring oscillators may be configured to inject bits into the ring generator at different locations from outputs of some or all its inverting elements. The random number generator may further comprise blocking circuitry configured to convert, based on a blocking signal, the ring generator into a circular shift register by blocking both the injection from the plurality of inverter-based ring oscillators and internal feedbacks in the ring generator.