Convenient key distribution

Christian Kurtsiefer, Patrick Zarda, M. Halder +4 more

Milo Grillo, Alexis A. Dowhuszko, Mohammad‐Ali Khalighi +1 more

Quantum Key Distribution (QKD) is a technology that enables the exchange of private encryption keys between two legitimate parties, using protocols that involve quantum mechanics principles. The rate at which secret keys can be exchanged depends on the attenuation that is experienced. Therefore, it is more convenient to replace many terrestrial fiber segments (and repeaters) by just few optical satellite links that would enable flexible global coverage. Then, the satellite nodes can take the role of trusted-relays, forwarding the secret keys from source to destination. However, since the rate at which secret keys can be generated in each quantum link is limited, it is very important to select the intermediate satellite nodes to inter-connect ground stations efficiently. This paper studies the most convenient allocation of resources in a QKD network that combines complementary connectivity services of GEO and LEO satellites. The aim of the centralized routing algorithm is to select the most convenient trusted-relays to forward the secret keys between pairs of ground stations, verifying the constraints that satellite-to-ground and inter-satellite quantum channels have.

Kim‐Kwang Raymond Choo

Xin Huang, Li Shu-Min, Wang An-Min

By comparing Cabello's addendum to his quantum key distribution protocol [Phys. Rev. A 64 (2001) 024301], we propose a more convenient modified protocol based on the entanglement swapping which is secure against the eavesdropping strategy addressed by Zhang et al. [Phys. Rev. A 63 (2001) 036301] and other existing types of attack.

László Gyöngyösi, Sándor Imre

Summary In this letter, we derive the maximal achievable secret key rates for continuous‐variable quantum key distribution (CVQKD) over free‐space optical (FSO) quantum channels. We provide a channel decomposition for FSO‐CVQKD quantum channels and study the SNR (signal‐to‐noise ratio) characteristics. The analytical derivations focus particularly on the low‐SNR scenarios. The results are convenient for wireless quantum key distribution and for the quantum Internet.

N. Alexandris