Realization of Quantum Digital Signatures without the Requirement of Quantum Memory

Robert J. Collins, Ross J. Donaldson, Vedran Dunjko, Petros Wallden, Patrick J. Clarke, Erika Andersson, John Jeffers, Gerald S. Buller

Research output: Contribution to journalArticlepeer-review


Digital signatures are widely used to provide security for electronic communications, for example, in financial transactions and electronic mail. Currently used classical digital signature schemes, however, only offer security relying on unproven computational assumptions. In contrast, quantum digital signatures offer information-theoretic security based on laws of quantum mechanics. Here, security against forging relies on the impossibility of perfectly distinguishing between nonorthogonal quantum states. A serious drawback of previous quantum digital signature schemes is that they require long-term quantum memory, making them impractical at present. We present the first realization of a scheme that does not need quantum memory and which also uses only standard linear optical components and photodetectors. In our realization, the recipients measure the distributed quantum signature states using a new type of quantum measurement, quantum state elimination. This significantly advances quantum digital signatures as a quantum technology with potential for real applications.
Original languageEnglish
Article number040502
Number of pages5
JournalPhysical Review Letters
Issue number4
Publication statusPublished - 21 Jul 2014


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