Optimization of Secure Quantum Key Distribution Backbones in Core Transport Networks

Abstract

We present a Mixed Integer Linear Programming formulation to perform optimal placement of Quantum Key Distribution devices to protect active/planned traffic at minimal cost, thus securing active core transport networks.

Optimal Design of Practical Quantum Key Distribution Backbones for Securing CoreTransport Networks

“…In this section, we evaluate the performance of the two proposed MILP models, and compare it to that of a previously published model from literature [11], which we named 'SoA' in this work.…”

“…The first formulation we discuss, an improvement over the one we presented in [11] and which we named Forced Direction (MForced) model, contains two types of variables: (i) S s,d…”

“…(u,v) variables. Compared to our previous model in [11], this one is similar (and indeed computes the same optimal solutions) but forgoes the need for a large number of binary variables, which ought to result in non-trivial execution speed gains.…”

“…In this paper we expand on a previous answer [11] to the question: if we were to deploy QKD in a terrestrial core transport network tomorrow, how could we do it effectively? That is, if the threat of quantum computers and/or the emergence of some new attack on Public Key Infrastructure forced us to deploy QKD technology in the short term, how could we do it in a manner that is both economical and guarantees adequate security in the presence of (classical) repeater sites?…”

“…We present two answers to these questions, in the form of two Mixed-Integer Linear Programming (MILP) formulations. The first is an improvement over our previous solution [11] in terms of execution time, due to using many fewer integer variables; the second new model accounts for the fact that key distribution need not follow the direction of the traffic, and, despite being significantly more complex and hence slower, can produce better (i.e., cheaper) QKD configurations which may well be significant if the cost of devices remains high.…”