cryptography Article QUARC: Quantum Research Cubesat—A Constellation for Quantum Communication Luca Mazzarella 1,∗,† , Christopher Lowe 2 , David Lowndes 3 , Siddarth Koduru Joshi 3 , Steve Greenland 4, Doug McNeil 4, Cassandra Mercury 4, Malcolm Macdonald 2, John Rarity 3 and Daniel Kuan Li Oi 1 1 SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK;
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[email protected] (J.R.) 4 Craft Prospect ltd. Tontine building, 20 Trongate, Glasgow G1 5ES, UK;
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[email protected] † Current address: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 298-102, Pasadena, CA 91109, USA. Received: 23 December 2019; Accepted: 21 February 2020; Published: 27 February 2020 Abstract: Quantum key distribution (QKD) offers future proof security based on fundamental laws of physics. Long-distance QKD spanning regions such as the United Kingdom (UK) may employ a constellation of satellites. Small satellites, CubeSats in particular, in low Earth orbit are a relatively low-cost alternative to traditional, large platforms.