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Quantum key distribution (QKD) promises provably secure cryptography, even to attacks from an all-powerful adversary. However, with quantum computing development lagging behind QKD, the assumption that there exists an adversary equipped…

Quantum Physics · Physics 2020-07-01 L. C. G. Govia , D. Bunandar , J. Lin , D. Englund , N. Lütkenhaus , H. Krovi

Quantum key distribution (QKD) exploits the quantum nature of light to share provably secure keys, allowing secure communication in the presence of an eavesdropper. The first QKD schemes used photons encoded in two states, such as…

We present strong attacks against quantum key distribution schemes which use quantum memories and quantum gates to attack directly the final key. We analyze a specific attack of this type, for which we find the density matrices available to…

Quantum Physics · Physics 2016-09-08 E. Biham , T. Mor

We give the first systematic study on the second order asymptotics of the operational task of coherence distillation with and without assistance. In the unassisted setting, we introduce a variant of randomness extraction framework where…

Quantum Physics · Physics 2021-10-29 Masahito Hayashi , Kun Fang , Kun Wang

The decoy state protocol has been considered to be one of the most important methods to protect the security of quantum key distribution (QKD) with a weak coherent source. Here we test two experimental approaches to generating the decoy…

Quantum Physics · Physics 2018-09-18 Anqi Huang , Shi-Hai Sun , Zhihong Liu , Vadim Makarov

Quantum key distribution is a way to distribute secret keys to distant users with information theoretic security and key rates suitable for real-world applications. Its rate-distance figure, however, is limited by the natural loss of the…

Quantum Physics · Physics 2018-09-12 Kiyoshi Tamaki , Hoi-Kwong Lo , Wenyuan Wang , Marco Lucamarini

We propose a quantum key distribution (QKD) protocol that is carried out in an indefinite causal order (ICO). In QKD, one considers a setup in which two parties, Alice and Bob, share a key with one another in such a way that they can detect…

Quantum Physics · Physics 2025-12-08 Hector Spencer-Wood

We consider the distribution of secret keys, both in a bipartite and a multipartite (conference) setting, via a quantum network and establish a framework to obtain bounds on the achievable rates. We show that any multipartite private…

Quantum Physics · Physics 2021-11-01 Siddhartha Das , Stefan Bäuml , Marek Winczewski , Karol Horodecki

In this paper, we consider continuous-variable quantum key distribution (QKD) protocols which use non-Gaussian modulations. These specific modulation schemes are compatible with very efficient error correction procedures, hence allowing the…

Quantum Physics · Physics 2015-03-17 Anthony Leverrier , Philippe Grangier

Security bounds for key distribution protocols using coherent and squeezed states and homodyne measurements are presented. These bounds refer to (i) general attacks and (ii) collective attacks where Eve interacts individually with the sent…

Quantum Physics · Physics 2009-11-10 Miguel Navascues , Antonio Acin

In this paper, we show that there are instances where eavesdropping causes noise reduction for a quantum key distribution (QKD) protocol. To witness these phenomena, we investigate a fault-tolerant six-state QKD protocol over a collective…

Quantum Physics · Physics 2023-07-18 Hiroo Azuma

Quantum key distribution (QKD) enables secure key sharing between distant parties, with several protocols proven resilient against conventional eavesdropping strategies. Here, we introduce a new attack scenario where an eavesdropper, Eve,…

Quantum Physics · Physics 2025-02-11 Sumit Nandi , Biswaranjan Panda , Pankaj Agrawal , Arun K Pati

The continuous variable quantum key distribution is expected to provide high secret key rate without single photon source and detector, but the lack of the secure and effective key distillation method makes it unpractical. Here, we present…

Quantum Physics · Physics 2007-05-23 Yi-bo Zhao , Zheng-fu Han , Jin-jian Chen , You-zhen Gui , Guang-can Guo

Nowadays security in communication is increasingly important to the network communication because many categories of data are required restriction on authorization of access, modify, delete and insert. Quantum cryptography is one of the…

Cryptography and Security · Computer Science 2011-06-23 Ajit Singh , Nidhi Sharma

Quantum key distribution promises information-theoretically secure communication, with data post-processing playing a vital role in extracting secure keys from raw data. While hardware advancements have significantly improved practical…

Quantum Physics · Physics 2025-12-01 Zhenyu Du , Guoding Liu , Xingjian Zhang , Xiongfeng Ma

Here we concerned with quantum key distribution - a way to establish common cryptographic key between several parties. The work proposes a combination between quantum key distribution and systematic polar coding (an error correction…

Quantum Physics · Physics 2025-11-25 Georgi Bebrov

Quantum key distribution (QKD) which enables information-theoretically security is now heading towards quantum secure networks. It requires high-performance and cost-effective protocols while increasing the number of users. Unfortunately,…

Quantum Physics · Physics 2023-02-07 Yiming Bian , Yi-Chen Zhang , Chao Zhou , Song Yu , Zhengyu Li , Hong Guo

We expand the recently discussed continuous-variable quantum key distribution scheme of Heid and Luetkenhaus (2006) to qudits with a lossy but noiseless quantum channel. Postselection methods are used. Secret key rates are calculated in the…

Quantum Physics · Physics 2009-03-12 Ulrich Seyfarth

Continuous-variable (CV) quantum key distribution (QKD) employs the quadratures of a bosonic mode to establish a secret key between two remote parties, and this is usually achieved via a Gaussian modulation of coherent states. The resulting…

Practical quantum key distribution (QKD) systems operate under noise, but security of most protocols have been analyzed under ideal noiseless scenarios. In this work, we investigated security performance of BB84 protocol under effect of…

Quantum Physics · Physics 2026-05-21 Wajiha Masood , Muhammad Waseem , Afshan Irshad