  Quantum key distribution (QKD) networks provide an infrastructure for
establishing information-theoretic secure keys between legitimate parties via
quantum and authentic classical channels. The deployment of QKD networks in
real-world conditions faces several challenges, which are related in particular
to the high costs of QKD devices and the condition to provide reasonable secret
key rates. In this work, we present a QKD network architecture that provides a
significant reduction in the cost of deploying QKD networks by using optical
switches and reducing the number of QKD receiver devices, which use
single-photon detectors. We describe the corresponding modification of the QKD
network protocol. We also provide estimations for a network link of a total of
670 km length consisting of 8 nodes, and demonstrate that the switch-based
architecture allows achieving significant resource savings of up to 28%, while
the throughput is reduced by 8% only.
