A Tutorial on Quantum Key Distribution Protocols With Interactive Simulation of QBER and SKR Performance Metrics

ABSTRACT In recent years, Quantum Key Distribution (QKD) has experienced rapid advancements, leading to widespread practical applications and drawing considerable attention from both academic and commercial sectors. Consequently, there has also been a growing interest in investigating the performance and efficiency of various QKD protocols. In this tutorial paper, we present a theoretical simulation‐based review of several QKD protocols, such as BB84, Decoy State BB84, Coherent One Way (COW), Differential Phase Shift (DPS), and the entanglement‐based BBM92 and E91 protocols. We simulate the Quantum Bit Error Rate (QBER) and Secret Key Rate (SKR) under varying parameters to provide a deeper understanding of their performance and inner workings. In addition to the simulation results, we introduce a web‐based graphical user interface (GUI) that allows users to interactively explore protocol behaviour and visualise the impact of various system parameters on the QBER and SKR of the QKD protocols. This tutorial aims to offer an intuitive understanding of various QKD protocols from an engineering perspective, using accessible simulation and visual analysis tools.