Security of Decoy-State Quantum Key Distribution with Correlated Intensity Fluctuations

Sixto, Xoel; Zapatero, Víctor; Curty, Marcos

doi:10.1103/physrevapplied.18.044069

Cited by 16 publications

(6 citation statements)

References 54 publications

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“…This has been observed in other QKD transmitter designs too, not related to our new approach introduced here. The study of such real-world encoding imperfections is a topic in its own right and various solutions have been proposed including variations to the security proofs and post-processing [29,30].…”

Section: Resultsmentioning

confidence: 99%

Simplified intensity- and phase-modulated transmitter for modulator-free decoy-state quantum key distribution

Woodward

Walk

et al. 2023

APL Photonics

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Quantum key distribution (QKD) allows secret key exchange between two users with unconditional security. For QKD to be widely deployed, low cost and compactness are crucial requirements alongside high performance. Currently, the majority of QKD systems demonstrated rely on bulk intensity and phase modulators to generate optical pulses with precisely defined amplitude and relative phase difference—i.e., to encode information as signal states and decoy states. However, these modulators are expensive and bulky, thereby limiting the compactness of QKD systems. Here, we present and experimentally demonstrate a novel optical transmitter design to overcome this disadvantage by generating intensity- and phase-tunable pulses at GHz clock speeds. Our design removes the need for bulk modulators by employing directly modulated lasers in combination with optical injection locking and coherent interference. This scheme is, therefore, well suited to miniaturization and photonic integration, and we implement a proof-of-principle QKD demonstration to highlight potential applications.

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Section: Resultsmentioning

confidence: 99%

Simplified intensity- and phase-modulated transmitter for modulator-free decoy-state quantum key distribution

Woodward

Walk

et al. 2023

APL Photonics

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“…Precisely, we assume that (A3) Alice's choice of intensities and the phase of her pulses are independent; (A4) Alice's (bit-and-basis) encoding operations commute with the process that (imperfectly) randomises the phase of her pulses; (A5) Alice's choice of bit, basis and intensity for round i only affects the ith pulse; (A6) Alice's encoding operations are characterised and identical for all rounds; (A7) the intensities of Alice's pulses perfectly match her choices; and (A8) the efficiency of Bob's measurement is independent of his basis choice. We note that previous works have investigated the security of QKD when some of these assumptions are not met [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42].…”

Section: Assumptions Of Our Proofmentioning

confidence: 99%

Security of quantum key distribution with imperfect phase randomisation

Currás-Lorenzo,

Nahar,

Lütkenhaus

et al. 2023

Quantum Sci. Technol.

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The performance of quantum key distribution (QKD) is severely limited by multiphoton emissions, due to the photon-number-splitting attack. The most efficient solution, the decoy-state method, requires that the phases of all transmitted pulses are independent and uniformly random. In practice, however, these phases are often correlated, especially in high-speed systems, which opens a security loophole. Here, we address this pressing problem by providing a security proof for decoy-state QKD with correlated phases that offers key rates close to the ideal scenario. Our work paves the way towards high-performance secure QKD with practical laser sources, and may have applications beyond QKD.

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“…Quantum key distribution (QKD) [1,2] is grounded in the fundamental principles of quantum mechanics, enabling the theoretical attainment of unconditionally secure communication. QKD has made substantial theoretical progress [3][4][5][6][7][8][9] and achieved successful experimental demonstrations [10][11][12][13][14][15][16][17][18]. Moreover, several QKD networks have been reported [19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Boosting asymmetric measurement-device-independent quantum key distribution via numerical-analysis technology

Li,

Zheng,

Zhang

et al. 2024

Phys. Scr.

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Asymmetric measurement-device-independent quantum key distribution (MDI-QKD) enables building a scalable, high-rate quantum network with an untrusted relay in real-world scenarios. In this study, we improve the performance of asymmetric MDI-QKD using numerical analysis techniques. Simulation results show a twofold increase in tolerance to basis misalignment compared to the previous state-of-the-art method. Specifically, for instances of substantial basis misalignment, the key rate increases by an order of magnitude, and the maximum communication distance extends by 20 km. Our work significantly enhances the robustness and feasibility of asymmetric MDI-QKD, thereby promoting the widespread deployment of MDI-QKD networks.

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Security of Decoy-State Quantum Key Distribution with Correlated Intensity Fluctuations

Cited by 16 publications

References 54 publications

Simplified intensity- and phase-modulated transmitter for modulator-free decoy-state quantum key distribution

Simplified intensity- and phase-modulated transmitter for modulator-free decoy-state quantum key distribution

Security of quantum key distribution with imperfect phase randomisation

Boosting asymmetric measurement-device-independent quantum key distribution via numerical-analysis technology

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