01633nas a2200169   4500000000100000008004100001260001500042100001600057700002100073700002400094700001900118700002200137245012200159856003700281300000700318520113800325       2026                            d  c07/10/20261 aAdam Bílek1 aRyszard Kukulski1 aPaulina Lewandowska1 aŁukasz Pawela1 aZbigniew Puchała00aNoise Resilience of Quantum Key Distribution Protocols Secured Against Independent Attacks With One-Way Communication  uhttps://arxiv.org/abs/2607.11857  a193 aWe investigate the resilience to noise of single-qubit quantum key distribution (QKD) protocols in the scenario of security against independent eavesdropping attacks and key distillation based on one-way classical communication. To this end, we introduce a noise-based metric that quantifies the efficiency of QKD protocols. Within this framework, we analyze the maximal noise levels that allow Alice and Bob to asymptotically establish a secure secret key. Using this assumption, we compare the noise tolerance of general single-qubit QKD protocols, in particular the BB84, B92, E91, and six-state protocols. Our main result determines the noise level threshold for QKD allowing one to distill an asymptotically secure secret key. Additionally, we demonstrate that the six-state protocol achieves the greatest resistance to noise while simultaneously yielding a higher post-selection efficiency than the other analyzed single-qubit protocols, confirming its robustness within the considered security model. Finally, we perform an analysis of the proposed noise-based metric and the conventional quantum bit error rate (QBER) metric.