PaQKD: Optimizing Qubit Retention in Quantum Key Distribution Using Packeting

Quantum Key Delivery (QKD) enables next generation cryptography, which is able to remain secure past the advent of quantum supremacy. Current protocols such as BB84 enable sharing private keys using properties of qubits, and allow users to check for eavesdroppers. However, these protocols suffer from low qubit retention rates, requiring up to four times the key length of potentially expensive qubits to be sent. Additionally, if an eavesdropper is detected, the entire key must be discarded. In this paper, we propose an improvement to the BB84 protocol, a packeting based protocol called PaQKD. PaQKD uses periodic checks in order to catch eavesdroppers during the process instead of only checking at the end of transmission, enabling users preserve a partial key. Simulations show that PaQKD significantly improves qubit retention rate as well, whether an eavesdropper is present or not, with insignificant loss of detection.