Metastable Latch PUF Circuit for On-Demand Random Number Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional techniques for generating true random numbers and Physically Unclonable Function (PUF) entropy sources in embedded systems lack dynamic triggering and error tolerance, relying on power-up cycles and voltage bias, making them unreliable for long-term use and unable to provide on-demand random numbers and unique device identities.
Innovation Solution
A circuit design that integrates true random number generation and PUF entropy source using hardware circuitry, capable of being dynamically triggered and independent of power-up cycles or pseudo-random number generator algorithms, utilizing a single array of PUF cell units with counter and collector circuits to generate both static and dynamic entropy for secure cryptographic applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional techniques use power-up cycle and voltage bias to generate random numbers, then the circuit can generate true random numbers, but the system cannot dynamically trigger the random number generation on-demand
Solution Approach 1:
The patent transforms the static power-up cycle-based random number generation into a dynamic system that can be triggered on-demand during operation. The PUF cell array can be activated at any time through control signals, allowing the system to generate random numbers dynamically rather than only during power-up sequences.
Solution Approach 2:
The PUF cell array serves multiple functions: it generates true random numbers for cryptographic applications, provides unique device identifiers through PUF characteristics, and can operate both as a static power-up resource and as a dynamic on-demand generator. This multi-functionality resolves the contradiction by making the same circuit serve both static and dynamic requirements.
2Reliability
If conventional PUF techniques are used without error tolerance, then the system can provide unique device IDs, but the system becomes unreliable for long-term use
Solution Approach 1:
The patent incorporates error correction coding and metastable bit removal circuits that are prepared in advance to handle potential measurement errors. These circuits are designed beforehand to correct errors that may occur during PUF cell state measurements, ensuring reliable operation over the long term without requiring complex real-time error handling.
Solution Approach 2:
The system uses feedback mechanisms where the output of PUF cells is measured and fed into error correction circuits that can detect and correct measurement errors. The feedback loop ensures that even if individual PUF cell states are unreliable, the final extracted random bits or device IDs maintain high reliability through iterative correction processes.
3Productivity
If PUF circuitry is executed only once at power-up, then the circuit can generate a root seed, but the result cannot be retrieved on-demand for private keys or digital signatures
Solution Approach 1:
The patent enables continuous operation of the PUF circuitry by removing the restriction to single power-up execution. The PUF cell array can be repeatedly activated during device operation to generate random numbers continuously, maintaining the useful action of random number generation throughout the device's operational lifetime rather than limiting it to a single power-up event.
Solution Approach 2:
The system performs preliminary setup of the PUF cell array during manufacturing or initialization, establishing the physical unclonable characteristics once. After this preliminary action, the same PUF structure can be repeatedly queried to generate random numbers on-demand, leveraging the pre-established physical characteristics without requiring re-initialization at each power-up cycle.
Data Source
AI summary
A triggerable circuitry for a Physically Unclonable Function (PUF) source and true random number generator comprises an array of metastable latches PUF cells units that produce output states in racing configuration dependent on manufacturing variations and noise fed into a counting circuit. The technology as a single circuit extracts detected random bits' states for true random numbers generation, different each time when requested, and is able to feed a PUF recovery system that will use the fairly static bits' patterns of the measured circuit although each time different.