Continuous-variable quantum digital signatures over insecure channels

Matthew Thornton, Hamish Scott, Callum Croal, Natalia Korolkova

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Digital signatures ensure the integrity of a classical message and the authenticity of its sender. Despite their far-reaching use in modern communication, currently used signature schemes rely on computational assumptions and will be rendered insecure by a quantum computer. We present a quantum digital signatures (QDS) scheme whose security is instead based on the impossibility of perfectly and deterministically distinguishing between quantum states. Our continuous-variable (CV) scheme relies on phase measurement of a distributed alphabet of coherent states and allows for secure message authentication against a quantum adversary performing collective beamsplitter and entangling-cloner attacks. Crucially, in the CV setting we allow for an eavesdropper on the quantum channels and yet retain shorter signature lengths than previous protocols with no eavesdropper. This opens up the possibility to implement CV QDS alongside existing CV quantum key distribution platforms with minimal modification.
Original languageEnglish
Article number032341
Number of pages10
JournalPhysical Review. A, Atomic, molecular, and optical physics
Issue number3
Early online date25 Mar 2019
Publication statusPublished - Mar 2019


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