Hardware software true random number generator based on a semiconductor photodiode array and logical combinations of cellular automata

Serhii Yanushevskyi; Yuriy Dobrovolsky

doi:10.15222/TKEA2026.1.32

Serhii Yanushevskyi Yurii Fedkovych Chernivtsi National University, Ukraine https://orcid.org/0009-0007-3426-2868
Yuriy Dobrovolsky Yurii Fedkovych Chernivtsi National University, Ukraine https://orcid.org/0000-0003-0626-0594

DOI: https://doi.org/10.15222/TKEA2026.1.32

Keywords: cellular automata, photodiode array, random number generator, data post processing, NIST STS tests, generation speed, cryptographic strength, information security, software engineering

Abstract

Primary binary sequences obtained directly from semiconductor photodiode arrays of standard CMOS webcams exhibit significant non-uniform frequency distributions and high inter-frame correlation. Experimental measurements reveal critical defects, including anomalous byte gaps in the [0...25] range and a 30% correlation in darkness. Primary binary sequences obtained directly from semiconductor photodiode arrays of standard CMOS webcams exhibit significant non-uniform frequency distributions and high inter-frame correlation. Experimental measurements reveal critical defects, including anomalous byte gaps in the [0...25] range and a 30% correlation in darkness. The primary entropy source is the stochastic photocurrent of the array elements, captured at 25 frames per second and transformed into discrete numbers via analog-to-digital conversion. Local statistical correlations are eliminated using post-processing based on logical combinations of one-dimensional cellular automata. The developed algorithm combines chaotic rule-switching and a multi-component XOR-MIX combination of equivalent primitives.. For high computational efficiency, a lightweight algorithm for adaptive control of evolution iterations based on express root-mean-square deviation control is introduced. The low complexity of bitwise Boolean operations enables real-time data processing on personal computers and embedded microcontrollers. Experimental results show that the developed algorithm provides a real-time generation speed of 47.8 Mbps, with an additional CPU load of only 0.3% and a frame latency of less than 0.1 ms. The normalized stream completely eliminates inherent hardware defects, successfully passing all 15 NIST STS test groups with a stable proportion of over 96%, confirming the cryptographic strength of the method and its high suitability for modern information security applications.

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