Quantum key distribution with phase-encoded coherent states: Asymptotic security analysis in thermal-loss channels

Papanastasiou, Panagiotis; Lupo, Cosmo; Weedbrook, Christian; Pirandola, Stefano

doi:10.1103/physreva.98.012340

Cited by 37 publications

(33 citation statements)

References 64 publications

(87 reference statements)

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“…Our security proof relied on several assumptions which reflect the state-of-the-art of CV quantum cryptography with our chosen alphabet, but which future work should endeavour to relax [24,25,31,32]. Firstly, the eavesdropping attacks permitted by a malevolent Bob in this work do not give him the full power afforded by quantum mechanics.…”

Section: Discussionmentioning

confidence: 99%

“…We focus on the quadrature phase-shift keying (QPSK) alphabet of 4 phase-encoded coherent states, denoted A 4 [24,25,29] distributed equally around the axis in phase space ( Fig. 1, inset).…”

Section: Protocol Descriptionmentioning

confidence: 99%

“…(12), (17). The states |Ψ B ′ 1 B2C and ρ j B|c (n) are derived in Appendix C. Finally, we note that Charlie's probability of measuring c ∈ C when Alice sends state |α k through the channel with transmission T and thermal noise input ρ th (n) is [25]…”

Section: Entangling Cloner Attackmentioning

confidence: 99%

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Continuous-variable quantum digital signatures over insecure channels

et al. 2019

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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, for the first time 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 (QKD) platforms with minimal modification.

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Section: Discussionmentioning

confidence: 99%

Section: Protocol Descriptionmentioning

confidence: 99%

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Continuous-variable quantum digital signatures over insecure channels

et al. 2019

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“…In a conventional non-Gaussian/discrete modulation protocol, a particular finite constellation of coherent states is considered and used for encoding data. A constellation of four and eight coherent states are the well-known cases [23,[30][31][32][33]. In this study, we focus on the QPSK protocol.…”

Section: A Modulation and Detectionmentioning

confidence: 99%

Discrete-Modulation Continuous-Variable Quantum Key Distribution Enhanced by Quantum Scissors

Ghalaii

Ottaviani

Kumar

et al. 2020

IEEE J. Select. Areas Commun.

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It is known that quantum scissors, as non-deterministic amplifiers, can enhance the performance of Gaussianmodulated continuous-variable quantum key distribution (CV-QKD) in noisy and long-distance regimes of operation. Here, we extend this result to a non-Gaussian CV-QKD protocol with discrete modulation. We show that, by using a proper setting, the use of quantum scissors in the receiver of such discrete-modulation CV-QKD protocols would allow us to achieve positive secret key rates at high loss and high excess noise regimes of operation, which would have been otherwise impossible. This also keeps the prospect of running discrete-modulation CV-QKD over CV quantum repeaters alive.

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“…We note that such a scheme has been employed successfully for quantum fingerprinting [31,32] and to establish quantum digital signatures [33]. The use of such states has been considered, also, for direct (Alice to Bob) QKD [34]. Twin-field QKD as originally introduced uses global phase randomization between Alice and Bob [26]; other techniques such as decoy states are also discussed elsewhere [27,28].…”

Section: Twin-field Protocolmentioning

confidence: 99%

Optimized attacks on twin-field quantum key distribution

et al. 2019

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In twin-field quantum key distribution the two communicating parties, Alice and Bob, each send a weak coherent pulse to a third party stationed between them. The key bits are generated by interference between these pulses, with the results communicated to Alice and Bob. We consider optimized strategies for eavesdropping on the communication built upon state discrimination and quantum non-demolition measurements. We find that the best strategy comprises a two-step process but that even this does not compromise the security of the protocol.

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Quantum key distribution with phase-encoded coherent states: Asymptotic security analysis in thermal-loss channels

Cited by 37 publications

References 64 publications

Continuous-variable quantum digital signatures over insecure channels

Continuous-variable quantum digital signatures over insecure channels

Discrete-Modulation Continuous-Variable Quantum Key Distribution Enhanced by Quantum Scissors

Optimized attacks on twin-field quantum key distribution

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