Faking Bell Violations with Classical Light and Side-Channel Attacks
Year: 2026
Type: conference-paper
Abstract: Bell inequality tests certify the security of entanglement-based quantum communication protocols, assuming random, hidden-variable-free basis choices and non-reproducible violations using classical sources. In practice, device imperfections and side channels enable adversaries to fake violations with classical light. Prior works focused on passive measurement selection, exploiting fixed beam splitters, detector blinding, and coincidence-time loopholes. Here, we extend this to active basis-choice systems, modeling attacks where an adversary exploits side-channel leakage from the basis-selection control path to gain partial knowledge of Alice’s and Bob’s settings, then sends tailored classical polarized light pulses programmed in timing and polarization to mimic entangled correlations. Using a discrete-event simulator, we model both genuine entangled pairs and classical faking sources in a full photonic quantum communication system. We compute the CHSH parameter S for both. Results show the classical source achieves S in the Tsirelson range $\left( {2 < S \leq 2\sqrt 2 } \right)$, closely mimicking the entangled-source case when assessed using S. Thus, mitigating side-channel leakage, especially in slow basis switching systems, is essential for securing higher-layer quantum protocols.
Institution: Technische Universität Dresden
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W7166575833