Layered Quantum Key Distribution

TL;DR

This paper proposes a family of quantum key distribution protocols utilizing multi-partite high-dimensional quantum states to efficiently distribute shared keys among multiple users, including broadcast keys, with practical implementation considerations.

Contribution

Introduces a novel family of QKD protocols leveraging multi-partite high-dimensional states for flexible and efficient key sharing in quantum networks.

Findings

Protocols can implement any key structure within a network.

More efficient than bipartite QKD in channel usage.

Protocols are feasible with current quantum photonic technology.

Abstract

We introduce a family of QKD protocols for distributing shared random keys within a network of $n$ users. The advantage of these protocols is that any possible key structure needed within the network, including broadcast keys shared among subsets of users, can be implemented by using a particular multi-partite high-dimensional quantum state. This approach is more efficient in the number of quantum channel uses than conventional quantum key distribution using bipartite links. Additionally, multi-partite high-dimensional quantum states are becoming readily available in quantum photonic labs, making the proposed protocols implementable using current technology.