Overcoming Intensity Limits for Long-Distance Quantum Key Distribution

• URL: http://arxiv.org/abs/2412.20265v2
• Date: Thu, 02 Jan 2025 07:26:59 GMT
• Title: Overcoming Intensity Limits for Long-Distance Quantum Key Distribution
• Authors: Ibrahim Almosallam,
• Abstract summary: Quantum Key Distribution (QKD) enables the sharing of cryptographic keys secured by quantum mechanics. BB84 protocol assumed single-photon sources, but practical systems rely on weak coherent pulses vulnerable to photon-number-splitting attacks. We show that higher intensities can be securely permitted by applying Bayesian inference to estimate key parameters directly from observed data.
• Score: 0.0
• License:
• Abstract: Quantum Key Distribution (QKD) enables the sharing of cryptographic keys secured by quantum mechanics. The BB84 protocol assumed single-photon sources, but practical systems rely on weak coherent pulses vulnerable to photon-number-splitting (PNS) attacks. The Gottesman-Lo-L\"utkenhaus-Preskill (GLLP) framework addressed these imperfections, deriving secure key rate bounds under limited PNS. The Decoy-state protocol further improved performance by refining single-photon yield estimates, but still considered multi-photon states as insecure, limiting intensities and thereby constraining key rate and distance. Here, we show that higher intensities can be securely permitted by applying Bayesian inference to estimate key parameters directly from observed data rather than relying on worst-case assumptions. By raising the pulse intensity to 10 photons, we achieve 50 times the key rate and a 62.2% increase in operational range (about 200 km) compared to the decoy-state protocol. Furthermore, we accurately model after-pulsing using a Hidden Markov Model and reveal inaccuracies in decoy-state calculations that may produce erroneous key-rate estimates. By bridging theoretical security and real-world conditions, this Bayesian methodology provides a versatile post-processing step for many discrete-variable QKD protocols, advancing their reach, efficiency, and facilitating broader adoption of quantum-secured communication.

Related papers

• Characterising higher-order phase correlations in gain-switched laser sources with application to quantum key distribution [38.00713966087315]
  Multi-photon emissions in laser sources represent a serious threat for the security of quantum key distribution. We introduce experimental schemes to characterise the phase probability distribution of the emitted pulses. We demonstrate that an optimisation task over interferometric measures suffices in determining the impact of arbitrary order correlations.
  arXiv  Detail & Related papers  (2024-12-04T22:06:13Z)
• Superior decoy state and purification quantum key distribution protocols for realistic quantum-dot based single photon sources [0.35342120781147623]
  We experimentally emulate two simple-to-implement protocols that allow practical, far from ideal sub-Poissonian photon sources to outperform state-of-the-art WCS. By engineering the photon statistics of a quantum dot's biexciton-exciton cascade, we show that either a truncated decoy state protocol or a heralded purification protocol can be employed.
  arXiv  Detail & Related papers  (2024-09-12T11:07:50Z)
• Phase-Matching Quantum Key Distribution without Intensity Modulation [25.004151934190965]
  We propose a phase-matching quantum key distribution protocol without intensity modulation. Simulation results show that the transmission distance of our protocol could reach 305 km in telecommunication fiber. Our protocol provides a promising solution for constructing quantum networks.
  arXiv  Detail & Related papers  (2023-03-21T04:32:01Z)
• Quantum Key Distribution Using a Quantum Emitter in Hexagonal Boron Nitride [48.97025221755422]
  We demonstrate a room temperature, discrete-variable quantum key distribution system using a bright single photon source in hexagonal-boron nitride. We have generated keys with one million bits length, and demonstrated a secret key of approximately 70,000 bits, at a quantum bit error rate of 6%. Our work demonstrates the first proof of concept finite-key BB84 QKD system realised with hBN defects.
  arXiv  Detail & Related papers  (2023-02-13T09:38:51Z)
• Single-emitter quantum key distribution over 175 km of fiber with optimised finite key rates [45.82374977939355]
  We perform fibre-based quantum key distribution with a quantum dot frequency-converted to telecom wavelength. We demonstrate positive key rates up to 175 km in the regime. This result represents major progress towards the feasibility of long-distance single-emitter QKD networks.
  arXiv  Detail & Related papers  (2022-09-07T18:03:36Z)
• Efficient room-temperature molecular single-photon sources for quantum key distribution [51.56795970800138]
  Quantum Key Distribution (QKD) allows the distribution of cryptographic keys between multiple users in an information-theoretic secure way. We introduce and demonstrate a proof-of-concept QKD system exploiting a molecule-based single-photon source operating at room temperature and emitting at 785nm.
  arXiv  Detail & Related papers  (2022-02-25T11:52:10Z)
• Round-robin differential phase-time-shifting protocol for quantum key distribution: theory and experiment [58.03659958248968]
  Quantum key distribution (QKD) allows the establishment of common cryptographic keys among distant parties. Recently, a QKD protocol that circumvents the need for monitoring signal disturbance, has been proposed and demonstrated in initial experiments. We derive the security proofs of the round-robin differential phase-time-shifting protocol in the collective attack scenario. Our results show that the RRDPTS protocol can achieve higher secret key rate in comparison with the RRDPS, in the condition of high quantum bit error rate.
  arXiv  Detail & Related papers  (2021-03-15T15:20:09Z)
• Security of the decoy state method for quantum key distribution [0.0]
  Quantum cryptography or, more precisely, quantum key distribution (QKD) is one of the advanced areas in the field of quantum technologies. This paper is devoted to the decoy state method, a countermeasure against vulnerabilities caused by the use of coherent states of light for QKD protocols.
  arXiv  Detail & Related papers  (2021-01-25T14:33:04Z)
• Upper security bounds for coherent-one-way quantum key distribution [0.0]
  Coherent-one-way (COW) QKD has been introduced as a promising solution to overcome this limitation. Thanks to its experimental simplicity, the COW protocol is already used in commercial applications. We derive simple upper security bounds on its secret key rate, which demonstrate that it scales at most quadratically with the system's transmittance.
  arXiv  Detail & Related papers  (2020-06-30T15:20:08Z)
• Experimental composable security decoy-state quantum key distribution using time-phase encoding [19.037123608278602]
  We provide the rigorous finite-key security bounds for four-intensity decoy-state BB84 QKD against coherent attacks. We build a time-phase encoding system with 200 MHz clocked to implement this protocol, in which the real-time secret key rate is more than 60 kbps over 50 km single-mode fiber.
  arXiv  Detail & Related papers  (2020-02-25T04:59:43Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.