IEEE Photonics Technology Letters

Design, Implementation, and Validation of an Unclonable Speckle-Based TRNG

Ala H. Sabeeh, Tawfik Ismail, Doaa Youssef

Published Mar 26, 2026• 1 citation

Abstract

This paper presents a high-throughput true random number generator (TRNG) based on optical speckle patterns generated by illuminating natural plant leaves as biological physical unclonable functions (PUFs). A coherent He–Ne laser produces stochastic far-field speckle fields that are captured by a CMOS camera and converted into random bitstreams using a clearly defined post-processing pipeline. The full extraction procedure— including binary quantization, Von Neumann debiasing, and statistical balancing—is formalized in Algorithm 1 to support reproducibility. Experimental validation is performed using a 38-s dataset (1100 frames), and long-term stability is demonstrated through a 2-hour continuous recording. All evaluated segments show near-ideal entropy (0.9999991 bits/bit), balanced bit distributions, and zero-mean autocorrelation, confirming the robustness of the biological scattering medium over extended durations. After debiasing, the system achieves an effective throughput of approximately 75 Mbit/s, aligning with requirements for cryptographic and security-critical applications. The optical setup is compact and compatible with laser-diode sources and embedded imaging modules, enabling future development of portable, low-power speckle-based TRNG systems.

DOI: 10.1109/lpt.2026.3677740

Related papers

Blood-inspired random bit generation using microfluidics system

Inkwon Yoon, Jong Hyeok Han, Byeong Uk Park +1 more

The development of random number generators (RNGs) using speckle patterns is pivotal for secure encryption key generation, drawing from the recent statistical properties identified in speckle-based imaging. Speckle-based RNG systems generate a sequence of random numbers through the unpredictable and reproducible nature of speckle patterns, ensuring a source of randomness that is independent of algorithms. However, to guarantee their effectiveness and reliability, these systems demand a meticulous and rigorous approach. In this study, we present a blood-inspired RNG system with a microfluidics device, designed to generate random numbers at a rate of 5.5 MHz and a high-speed of 1250 fps. This process is achieved by directing a laser beam through a volumetric scattering medium to procure speckle patterns. Additionally, designed microfluidic device requires only a minimal blood sample of 5 µl to capture these speckle patterns effectively. After implementing the two-pass tuple-output von Neumann debiasing algorithm to counteract statistical biases, we utilized the randomness statistical test suite from the National Institute of Standards and Technology for validation. The generated numbers successfully passed these tests, ensuring their randomness and unpredictability. Our blood-inspired RNG, utilizing whole blood, offers a pathway for affordable, high-output applications in fields like encryption, computer security, and data protection.

Scientific ReportsMar 29, 20245 citations

Optical PUF-based random number generation using optical speckle patterns

Mutupuri Shiva Shankar, Vinny Cris Mandapati, MD. Haider Ansari +6 more

Random number generators (RNG) are fundamental to cryptographic systems, requiring high entropy, unpredictability, and resistance to cloning attacks. This work proposes RNG based on optical physical unclonable function (PUF) that uses random scattering of structured vortex beams through rough surface. The inherent disorder of the scattering medium with tunable beam parameters like vortex order, provides a rich source of physical randomness. The generated speckle patterns are processed using a post processing algorithm to produce random sequences at a rate of 1.42 Gbps. The statistical quality of the sequences is evaluated using the NIST SP 800-22, AIS-31, and Dieharder test suites, which meet the required randomness criteria. Further assessment using entropies and Kolmogorov complexity shows high entropy and algorithmic randomness. The physical unclonability and uniqueness are verified through inter-device hamming distances, Pearson correlation of sequences obtained from different spatial regions and vortex orders, revealing negligible correlations. To assess resilience against data based adversaries, machine learning modeling attacks are performed. The prediction accuracies remain close to random guessing, showing resistance to learning based cloning and response prediction attacks. These results establish the proposed optical PUF method as a high speed, physically unclonable, and machine learning resistant source of random numbers for secure cryptographic applications.

ArrayOct 19, 20260 citations

Fast random number generator based on optical physical unclonable functions

Kun Chen, Feng Huang, Pidong Wang +3 more

We propose an approach for fast random number generation based on homemade optical physical unclonable functions (PUFs). The optical PUF is illuminated with input laser wavefront of continuous modulation to obtain different speckle patterns. Random numbers are fully extracted from speckle patterns through a simple post-processing algorithm. Our proof-of-principle experiment achieves total random number generation rate of 0.96 Gbit/s with verified randomness, which is far faster than previous optical-PUF-based schemes. Our results demonstrate that the presented random number generator (RNG) proposal has great potential to achieve ultrafast random number generation rate up to several hundreds of Gbit/s.

arXiv:2109.03325Optics LettersSep 1, 202132 citations

Optical True Random Number Generator Based on Reconfigurable Ge2Sb2Te5 PUFs

Yiting Yang, Ruijie Hui, Xueguang Lu +7 more

True random number generators (TRNGs) are the fundamental building blocks for encryption. Physical unclonable functions (PUFs) prepared based on stochastic processes, with the advantages of being impossible to imitate and tamper with, are a new source for generating high-quality random numbers. However, most proposed PUFs form a fixed structure after preparation; the as-generated random number sequence is thus fixed. In this article, a reconfigurable optical PUF/TRNG is fabricated by utilizing the phase change properties of the disordered Ge 2 Sb 2 Te 5 (GST) nanocrystalline film. By heating and holding the GST film, its crystallization ratio can be manipulated, generating multiple sets of uncorrelated speckle patterns, which can be converted into multiple random arrays by binary digitization. The random array was verified to have good randomness by the National Institute of Standards and Technology (NIST) randomness test and the DIEHARD(ER) test suites. The proposed true random number generator can be used as a secret key to complete authentication or encryption with high security and high stability.

ACS PhotonicsOct 29, 20248 citations

Analysis of entropy source for random number generation based on optical PUFs

Kun Chen, Pidong Wang, Feng Chen Huang +2 more

In this paper, we present an in-depth analysis for entropy source based on optical physical unclonable functions (PUFs). The randomness of speckle patterns is elaborated essentially according to its statistical characteristics. Various factors affecting the source of entropy have been analyzed in detail, including wavefront modulation, sensitivity, and universality of the optical PUF, and bit-depth settings of captured speckle patterns. In view of the above considerations, we demonstrate that the entropy source can achieve an ultra-high min-entropy (>0.985 bits/bit) while maintaining a high extraction rate of 75% and also verify its independent and identically distributed nature. These results provide an in-depth and comprehensive understanding of the developed entropy source and offer a firm foundation for its practical use.

Journal of Applied PhysicsMay 1, 20239 citations

Microscopic statistical characterization of speckle patterns in optical physical unclonable functions for high-quality cryptographic key generation

Kun Chen, FENG HUANG, Pidong Wang +3 more

Optical physical unclonable functions (PUFs) are gaining significant attention in hardware security due to their intrinsically unpredictable quasi-chaotic behavior, rendering it particularly suitable for random key generation. However, systematic evaluation and quantitative criteria for speckle quality remain largely unexplored, with microscopic-level analyses still lacking, thereby severely hindering practical application. To address this, we conduct a comprehensive statistical and information-theoretic evaluation by extracting speckle information from diverse perspectives, with particular emphasis on the gray-level co-occurrence matrix and its higher-order statistical features. Accordingly, it is demonstrated that speckle patterns satisfying the sampling theorem reveal strong inherent randomness and are well suited for secret-key generation. Finally, we establish a quantitative speckle quality discrimination framework that integrates multiple information-theoretic means for high-quality cryptographic key generation. The resulting random bit streams successfully pass stringent Dieharder randomness tests and exhibit a verified min-entropy exceeding 0.995 bits per bit. Our results provide a potential research avenue for improving the randomness of optical PUF-based secret-key generation systems, advancing their real-world deployment in information security.

Optics ExpressAug 28, 20260 citations