Security of Device-independent Quantum Key Distribution under Sequential Attack

Fuente: arXiv
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Main Authors: Roy, Pritam, Sasmal, Souradeep, Bera, Subhankar, Gupta, Shashank, Roy, Arup, Majumdar, A. S.
Format: Preprint
Published: 2024
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author Roy, Pritam
Sasmal, Souradeep
Bera, Subhankar
Gupta, Shashank
Roy, Arup
Majumdar, A. S.
author_facet Roy, Pritam
Sasmal, Souradeep
Bera, Subhankar
Gupta, Shashank
Roy, Arup
Majumdar, A. S.
contents Device-independent quantum key distribution (DI-QKD) leverages nonlocal correlations to establish cryptographic keys between two honest parties while making minimal assumptions about the underlying systems. The security of DI-QKD is grounded in the validity of quantum theory, with Bell violations ensuring the intrinsic unpredictability of observed statistics, independent of the trustworthiness of the devices. While traditional collective QKD attacks assume that the adversary prepares the shared system, we analyse a scenario where the adversary does not control the source and instead interacts sequentially with the travelling system. In this setting, Eve performs an unsharp measurement that produces effective noise while preserving the observed Bell violation. Although such behaviour is already accounted for in existing DI-QKD security proofs, examining it through an explicit sequential interaction offers a concrete and physically motivated example of how these effective statistics can arise in practice. Our analysis further shows that, within a specific parameter regime, this sequential strategy reproduces some features of an optimal collective attack.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16822
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Security of Device-independent Quantum Key Distribution under Sequential Attack
Roy, Pritam
Sasmal, Souradeep
Bera, Subhankar
Gupta, Shashank
Roy, Arup
Majumdar, A. S.
Quantum Physics
Device-independent quantum key distribution (DI-QKD) leverages nonlocal correlations to establish cryptographic keys between two honest parties while making minimal assumptions about the underlying systems. The security of DI-QKD is grounded in the validity of quantum theory, with Bell violations ensuring the intrinsic unpredictability of observed statistics, independent of the trustworthiness of the devices. While traditional collective QKD attacks assume that the adversary prepares the shared system, we analyse a scenario where the adversary does not control the source and instead interacts sequentially with the travelling system. In this setting, Eve performs an unsharp measurement that produces effective noise while preserving the observed Bell violation. Although such behaviour is already accounted for in existing DI-QKD security proofs, examining it through an explicit sequential interaction offers a concrete and physically motivated example of how these effective statistics can arise in practice. Our analysis further shows that, within a specific parameter regime, this sequential strategy reproduces some features of an optimal collective attack.
title Security of Device-independent Quantum Key Distribution under Sequential Attack
topic Quantum Physics
url https://arxiv.org/abs/2411.16822