Optimal quantum key distribution networks: capacitance versus security

Abstract

The rate and security of quantum communications between users placed at arbitrary points of a quantum communication network depend on the structure of the network, on its extension and on the nature of the communication channels. In this work we propose a strategy for the optimization of trusted-relays based networks that intertwines classical network approaches and quantum information theory. Specifically, by suitably defining a quantum communication efficiency functional, we identify the optimal quantum communication connections through the network by balancing security and the quantum communication rate. The optimized network is then constructed as the network of the maximal quantum communication efficiency connections and its performance is evaluated by studying the scaling of average properties as functions of the number of nodes and of the network spatial extension.

Complex quantum networks: a topical review

“…Meanwhile, standardisation of mainly trusted node QKD networks but also others is pursued by several organizations (see [450] for a recent summary) and in particular the interplay between the network structure, key management policy and degree of practical security might benefit from further applications of network theory. Good examples of the latter include trading some rate to increased security using multiple [36] or single paths [518]. In particular, [518] introduces the concept of quantum efficiency to describe the tradeoff and maximum efficiency networks that optimize it, as well as an algorithm to find them for a given relative importance between rate and security.…”

“…Good examples of the latter include trading some rate to increased security using multiple [36] or single paths [518]. In particular, [518] introduces the concept of quantum efficiency to describe the tradeoff and maximum efficiency networks that optimize it, as well as an algorithm to find them for a given relative importance between rate and security. Alternatively, one may consider the case where only some of the nodes are trusted and ask about the connected components for a given maximum number of hops between trusted nodes.…”