Testing the BB84 Quantum Protocol Under Intercept-Resend Attacks

Abstract

This study evaluates the cryptographic resilience of the BB84 quantum key distribution protocol against intercept-resend attacks under realistic noise conditions. Utilizing Qiskitbased simulations, the work models eavesdropper detection through a binomial statistical framework across three experiments, transitioning from deterministic parameter evaluation to continuous, unpredictable adversarial scenarios. The results demonstrate that detection probability is inextricably linked to the interception fraction (p) and the evaluated qubit block size (n). Receiver Operating Characteristic (ROC) analysis and confusion matrices quantitatively reveal that small qubit blocks suffer from high statistical variance, allowing weak attacks to evade detection. Conversely, increasing the block size effectively mitigates false negatives and drastically improves diagnostic sensitivity. Ultimately, the analysis confirms that the BB84 protocol ensures reliable eavesdropper detection if the sample size is large enough to isolate quantum disturbances from background noise.