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arXiv · 2509.04389

An Optical Emulation of the BB84 Quantum Key Distribution Protocol

Alec L. Riso·Karthik Thyagarajan·Connor Whiting·Katherine Jimenez
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Abstract

Quantum key distribution (QKD) is an approach to secure communication that uses the principles of quantum mechanics to generate a shared secret key which can be used in encrypting messages. Unlike traditional cryptography, which relies on mathematical problems too computationally difficult for a classical computer to solve, an ideal QKD protocol can be secure even against the capabilities of quantum algorithms. The BB84 protocol, a famous implementation of QKD, uses the polarization states of photons to carry information. We constructed an accessible, fiber-optic-based apparatus that emulates the generation of a key through the BB84 protocol. Although a true demonstration of BB84 would require a single-photon regime, our many-photon system shows the information encoding, transmission, and basis-sifting steps of the protocol. Due to its accessibility and visual clarity, our apparatus is intended as an educational tool that makes each logical step of the protocol visible.

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Alec L. Riso, Karthik Thyagarajan, Connor Whiting, Katherine Jimenez. 2026-08-24. An Optical Emulation of the BB84 Quantum Key Distribution Protocol. https://arxiv.org/abs/2509.04389

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