True Random Number Generator Photon Flow Constraint
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Solution Overview
Problem
True random number generators based on quantum photonics face limitations in entropy level and bit rate due to variations in manufacturing quality, power supply, and environmental factors, requiring post-processing that increases complexity and reduces bit rate, while existing solutions to mitigate these issues either require complex electronic circuitry or compromise on entropy.
Innovation Solution
A true random number generator with a photon source and electronic sampling means configured such that the product of detected photon flow and observation window duration (λ*Tw) is less than or equal to 0.01, integrated into a single silicon substrate, ensuring a high entropy level and compact, less complex design with enhanced safety and economical benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If post-processing is applied to improve uniformity of probability distribution, then entropy level is improved, but bit rate is reduced
Solution Approach 1:
The patent changes the parameter λ*Tw (product of detected photon flow and observation window duration) to be less than or equal to 0.01, which fundamentally alters the statistical distribution of photon arrivals. This parameter change enables the system to achieve uniform probability distribution without requiring traditional post-processing, thereby maintaining high bit rate while ensuring high entropy level.
2Reliability
If complex electronic circuitry is added to mitigate variations, then reliability is improved, but device complexity increases
Solution Approach 1:
Instead of adding complex electronic circuitry to compensate for variations in manufacturing quality, power supply, and environmental factors, the patent changes the operational parameter λ*Tw to ≤0.01. This parameter change makes the system inherently robust against variations, eliminating the need for additional complex circuitry while maintaining high reliability.
Solution Approach 2:
The patent extracts and eliminates the need for complex post-processing circuitry and compensation mechanisms by fundamentally changing the operating regime. The solution removes unnecessary components and complexity while retaining or improving reliability through the optimized parameter regime.
3Productivity
If photon flow is increased to improve bit rate, then productivity is improved, but uniformity of distribution deteriorates
Solution Approach 1:
The patent identifies that the product λ*Tw (not just λ alone) determines the statistical properties. By constraining this product to ≤0.01, the system can operate at optimal photon flows for high bit rate while automatically achieving uniform probability distribution. This resolves the contradiction by showing that uniformity depends on the combined parameter, not just photon flow alone.
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 configuration achieves a substantially uniform distribution of photon arrival times, passing NIST statistical tests, with increased entropy and bit rate, while maintaining a compact and secure design with reduced energy consumption.
Implementation Method 1
the photons obey to a Poisson process, meaning that the acquired events are independent of one another and that the probability of counting n photons within an observation window Tw follows the Poisson distribution
Implementation Method 2
an attenuated light source generates few photons (low value of the detected photon flow λ) that are acquired by one or more detectors of individual photons, each one of which is known by the acronym SPAD (Single Photon Avalanche Diode)
Data Source
AI summary
A random number generator includes a photon source and one or more photon detectors of the SPAD type (311) configured to detect a photon flow equal to λ, wherein the photons are generated by the photon source. The random number generator furthermore includes an electronic sampler. The electronic sampler is configured in such a way as to detect the arrival time t of a photon incident on each SPAD photon detector (311) for each one of the observation windows Tw, and are also configured in such a way as to convert the arrival time t into a binary sequence. In the generator of the invention the photon source and the electronic sampler are configured in such a way that the product λ*Tw is lower than or equal to 0.01.