A Scalable Simulation of the BB84 Protocol Involving Eavesdropping

Abstract

In this article we present the BB84 quantum key distribution scheme from two perspectives. First, we provide a theoretical discussion of the steps Alice and Bob take to reach a shared secret using this protocol, while an eavesdropper Eve is either involved or not. Then, we offer and discuss two distinct implementations that simulate BB84 using IBM’s Qiskit framework, the first being an exercise solved during the “IBM Quantum Challenge” event in early May 2020, while the other was developed independently to showcase the intercept-resend attack strategy in detail. We note the latter’s scalability and increased output verbosity, which allow for a statistical analysis to determine the probability of detecting the act of eavesdropping