Delfina B. Amenta

Various tasks related to classical and quantum cryptography, as well as information security, rely extensively on genuine random numbers and random bits that are irreproducible, unbiased, and unpredictable. Consequently, generating these numbers is considered a critical task; the numerical sequences from which they are extracted cannot be generated deterministically using algorithms, as they could eventually be replicated. The non-deterministic nature of quantum systems appears as a natural source of entropy for this application. In this regard, a Quantum Random Number Generator (QRNG) emerges as a native solution to the problem of unpredictable random number generation. Under this premise, the objective of this work is to develop a randomness source based on the quantum characteristics of the photodetection process, along with its corresponding extractor. We present the development progress of a portable and modular device capable of generating arbitrary streams of uniform random bits based on the quantum fluctuations of photons emitted by a light-emitting diode (LED) and detected by a CMOS camera. We designed and implemented an optoelectronic system featuring active intensity control via a feedback loop. Raw image data is processed to acquire intensity values, and image capture parameters have been optimized to achieve a homogeneous illumination profile. For randomness generation, a noise model of the photodetection process was established, and a Toeplitz-hashing extractor was implemented based on a measured bound of the min-entropy.