Security of differential phase shift QKD from relativistic principles


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Date

2025-01-27

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

The design of quantum protocols for secure key generation poses many challenges: On the one hand, they need to be practical concerning experimental realisations. On the other hand, their theoretical description must be simple enough to allow for a security proof against all possible attacks. Often, these two requirements are in conflict with each other, and the differential phase shift (DPS) QKD protocol exemplifies these difficulties: It is designed to be implementable with current optical telecommunication technology, which, for this protocol, comes at the cost that many standard security proof techniques do not apply to it. After about 20 years since its invention, this work presents the first full security proof of DPS QKD against general attacks, including finite-size effects. The proof combines techniques from quantum information theory, quantum optics, and relativity. We first give a security proof of a QKD protocol whose security stems from relativistic constraints. We then show that security of DPS QKD can be reduced to security of the relativistic protocol. In addition, we show that coherent attacks on the DPS protocol are, in fact, stronger than collective attacks. Our results have broad implications for the development of secure and reliable quantum communication technologies, as they shed light on the range of applicability of stateof-the-art security proof techniques.

Publication status

published

Editor

Book title

Journal / series

Volume

9

Pages / Article No.

1611

Publisher

Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Organisational unit

03781 - Renner, Renato / Renner, Renato check_circle

Notes

Funding

188541 - Information-theoretic limits to time measurements (SNF)

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