{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T10:02:17Z","timestamp":1777629737596,"version":"3.51.4"},"reference-count":78,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,2,27]],"date-time":"2020-02-27T00:00:00Z","timestamp":1582761600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cryptography"],"abstract":"<jats:p>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. They allow the deployment of a large number of spacecrafts, ensuring greater coverage and mitigating some of the risk associated with availability due to cloud cover. We present our mission analysis showing how a constellation comprising 15 low-cost 6U CubeSats can be used to form a secure communication backbone for ground-based and metropolitan networks across the UK. We have estimated the monthly key rates at 43 sites across the UK, incorporating local meteorological data, atmospheric channel modelling and orbital parameters. We have optimized the constellation topology for rapid revisit and thus low-latency key distribution.<\/jats:p>","DOI":"10.3390\/cryptography4010007","type":"journal-article","created":{"date-parts":[[2020,2,28]],"date-time":"2020-02-28T09:30:36Z","timestamp":1582882236000},"page":"7","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":69,"title":["QUARC: Quantum Research Cubesat\u2014A Constellation for Quantum Communication"],"prefix":"10.3390","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6328-1135","authenticated-orcid":false,"given":"Luca","family":"Mazzarella","sequence":"first","affiliation":[{"name":"SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2964-7337","authenticated-orcid":false,"given":"Christopher","family":"Lowe","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of Strathclyde, Level 8, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2364-4373","authenticated-orcid":false,"given":"David","family":"Lowndes","sequence":"additional","affiliation":[{"name":"Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory &amp; Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4987-457X","authenticated-orcid":false,"given":"Siddarth Koduru","family":"Joshi","sequence":"additional","affiliation":[{"name":"Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory &amp; Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK"}]},{"given":"Steve","family":"Greenland","sequence":"additional","affiliation":[{"name":"Craft Prospect ltd. Tontine building, 20 Trongate, Glasgow G1 5ES, UK"}]},{"given":"Doug","family":"McNeil","sequence":"additional","affiliation":[{"name":"Craft Prospect ltd. Tontine building, 20 Trongate, Glasgow G1 5ES, UK"}]},{"given":"Cassandra","family":"Mercury","sequence":"additional","affiliation":[{"name":"Craft Prospect ltd. Tontine building, 20 Trongate, Glasgow G1 5ES, UK"}]},{"given":"Malcolm","family":"Macdonald","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of Strathclyde, Level 8, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ, UK"}]},{"given":"John","family":"Rarity","sequence":"additional","affiliation":[{"name":"Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory &amp; Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0965-9509","authenticated-orcid":false,"given":"Daniel Kuan Li","family":"Oi","sequence":"additional","affiliation":[{"name":"SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,27]]},"reference":[{"key":"ref_1","first-page":"157","article-title":"Elliptic curve cryptography in practice","volume":"Volume 8437","author":"Christin","year":"2014","journal-title":"Financial Cryptography and Data Security"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Alagic, G., Alagic, G., Alperin-Sheriff, J., Apon, D., Cooper, D., Dang, Q., Liu, Y.K., Miller, C., Moody, D., and Peralta, R. (2019). 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