S-Box TRNG Metastability High Bit Rate

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Solution Overview

Problem

Existing true random number generators (TRNGs) are limited in generating random numbers at high rates, are easily identifiable and influenceable, and often rely on analog or easily detectable digital entropy sources, making them vulnerable to attacks and difficult to integrate seamlessly with digital logic.

Innovation Solution

The use of substitution box (S-box) components in a series configuration, leveraging metastable states to generate random numbers at high rates, with a sampling circuit and post-processing to compress and synchronize outputs, making the entropy source compact, efficient, and difficult to identify or manipulate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional one-way ring oscillators are used for random number generation, then the TRNG can be implemented, but the bit rate is limited and the implementation is easily identifiable to probing attacks

Engineering Contradiction:
Improvebit rateVSAvoiddetectability to probing attacks
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The ring oscillator is segmented into multiple imaging devices (e.g., 4 imaging devices), each processing a portion of the input signals. This segmentation increases the complexity of the implementation, making it harder to identify and probe, while also enabling higher bit rates through parallel processing of multiple input signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a one-dimensional single-path ring oscillator to a multi-dimensional combinatorial imaging structure where n input signals are transformed into p output signals through multiple imaging devices arranged in feedback loops. This dimensional expansion enables higher bit rates and increased security against probing attacks.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If analog entropy sources are used, then random numbers can be generated, but the TRNG is easily identifiable and influenceable

Engineering Contradiction:
Improverandom number generation capabilityVSAvoididentifiability and influenceability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces traditional analog entropy sources with a digital combinatorial imaging system using logic circuits and imaging devices. This substitution eliminates the vulnerabilities of analog sources to identification and influence while maintaining reliable random number generation through the inherent unpredictability of the imaging transformations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If digital logic integration is improved, then seamless integration is achieved, but the TRNG becomes more identifiable

Engineering Contradiction:
Improveintegration with digital logicVSAvoididentifiability
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The imaging devices perform multiple functions: they process digital logic operations, generate random bits, and provide feedback loops for continuous operation. This multi-functionality enables seamless integration with digital logic systems while the complex imaging transformations maintain obscurity against identification.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach enables TRNGs to produce multiple megabytes of random numbers per second while being difficult to identify and influence, providing a secure and efficient source of entropy for cryptographic applications.

Implementation Method 1

The use of substitution box (S-box) components in a series configuration, leveraging metastable states to generate random numbers at high rates

Methodology Applied
Scientific EffectMetastability: Metastability

Data Source

PatentEP3106978B1Digital true random number generator based on s-boxes
Publication Date: 2018.03.14 NXP BV
  • EP3106978B1 patent drawingFigure 1
  • EP3106978B1 patent drawingFigure 2~3
  • EP3106978B1 patent drawingFigure 4

AI summary

Various embodiments described herein relate to a hardware device for generating random numbers including: a plurality of substitution boxes (S-Boxes) connected to each other in a series, wherein a plurality of bits output from an S-Box of the plurality of S-Boxes is input into another S-Box of the plurality of S-Boxes; a sampling circuit configured to sample bit strings from at least one S-Box of the plurality of S-Boxes.