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The security of quantum key distribution relies on the validity of quantum mechanics as a description of nature and on the non-existence of leaky degrees of freedom in the practical implementations. We experimentally demonstrate how, in…

Quantum Physics · Physics 2009-11-13 Antia Lamas-Linares , Christian Kurtsiefer

In conventional quantum key distribution protocols, the secure key is normally extracted from the measurement outcomes of the system. Here, a different approach is proposed, where the secure key is extracted from the measurement bases,…

Quantum Physics · Physics 2014-10-21 Xiongfeng Ma

We have developed a method to calculate a secret key rate of a continuous-variable quantum-key-distribution scheme using four coherent states and postselection for a general model of Gaussian attacks. We assume that the transmission line…

Quantum Physics · Physics 2018-10-30 Ryo Namiki , Akira Kitagawa , Takuya Hirano

There has been much interest in quantum key distribution. Experimentally, quantum key distribution over 150 km of commercial Telecom fibers has been successfully performed. The crucial issue in quantum key distribution is its security.…

Quantum Physics · Physics 2009-11-10 Hoi-Kwong Lo , Xiongfeng Ma , Kai Chen

In a deterministic quantum key distribution (DQKD) protocol with a two-way quantum channel, Bob sends a qubit to Alice who then encodes a key bit onto the qubit and sends it back to Bob. After measuring the returned qubit, Bob can obtain…

Quantum Physics · Physics 2011-11-02 Hua Lu , Chi-Hang Fred Fung , Xiongfeng Ma , Qing-yu Cai

We propose a multiple pulses phase-matching quantum key distribution protocol (MPPM-QKD) to exceed the linear key rate bound and to achieve higher error tolerance. In our protocol, Alice and Bob generate at first their own train pulses…

Quantum Physics · Physics 2019-05-28 Gang Chen , Le Wang , Wei Li , Qianping Mao , Zhigang Shen , Shengmei Zhao , Jozef Gruska

We discuss a quantum key distribution scheme in which small phase and amplitude modulations of quantum limited, CW light beams carry the key information. We identify universal constraints on the level of shared information between the…

Quantum Physics · Physics 2007-05-23 T. C. Ralph

A new and simple quantum key distribution scheme based on the quantum intensity correlation of optical twin beams and the directly local measurements of intensity noise of single optical beam is presented and experimentally demonstrated.…

Quantum Physics · Physics 2007-05-23 Xiaojun Jia , Xiaolong Su , Qing Pan , Kunchi Peng , Changde Xie

Quantum communication addresses the problem of exchanging information across macroscopic distances by employing encryption techniques based on quantum mechanical laws. Here, we advance a new paradigm for secure quantum communication by…

Quantum Physics · Physics 2021-05-19 R. Di Candia , H. Yiğitler , G. S. Paraoanu , R. Jäntti

We study the problem of secret key distillation from bipartite states in the scenario where Alice and Bob can only perform measurements at the single-copy level and classically process the obtained outcomes. Even with these limitations,…

Quantum Physics · Physics 2009-11-10 Antonio Acin , Lluis Masanes , Nicolas Gisin

In the original BB84 protocol by Bennett and Brassard, an eavesdropper is detected because his attempts to intercept information result in a quantum bit error rate (QBER) of at least 25%. Here we design an alternative quantum key…

Quantum Physics · Physics 2015-05-13 Muhammad Mubashir Khan , Michael Murphy , Almut Beige

A new protocol, quantum energy distribution (QED), is proposed in which multiple parties can simultaneously extract positive energy from spin chains by common secret keys shared by an energy supplier. QED is robust against impersonation; an…

Quantum Physics · Physics 2009-11-13 Masahiro Hotta

The laws of quantum mechanics allow for the distribution of a secret random key between two parties. Here we analyse the security of a protocol for establishing a common secret key between N parties (i.e. a conference key), using resource…

Quantum Physics · Physics 2017-11-13 Michael Epping , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruß

In this paper, we consider the problem of secret key generation with one-way communication through both a rate-limited public channel and a rate-limited secure channels where the public channel is from Alice to Bob and Eve and the secure…

Information Theory · Computer Science 2020-04-13 Yinfei Xu , Daming Cao

The continuous-variable quantum key distribution with entanglement in the middle, a semi-device-independent protocol, places the source at the untrusted third party between Alice and Bob, and thus has the advantage of high levels of…

Quantum Physics · Physics 2020-04-23 Yi-Chen Zhang , Ziyang Chen , Christian Weedbrook , Song Yu , Hong Guo

We propose a quantum key distribution scheme that combines a biased basis choice with the decoy-state method. In this scheme, Alice sends all signal states in the $Z$ basis and decoy states in the $X$ and $Z$ basis with certain…

Quantum Physics · Physics 2013-08-20 Zhengchao Wei , Weilong Wang , Zhen Zhang , Ming Gao , Zhi Ma , Xiongfeng Ma

We discuss quantum key distribution protocols using quantum continuous variables. We show that such protocols can be made secure against individual gaussian attacks regardless the transmission of the optical line between Alice and Bob. This…

Quantum Physics · Physics 2016-09-08 F. Grosshans , N. J. Cerf , J. Wenger , R. Tualle-Brouri , Ph. Grangier

We present a quantum key distribution protocol based on four-level particles entanglement. Furthermore, a controlled quantum key distribution protocol is proposed by utilizing three four-level particles. We show that the two protocols are…

Quantum Physics · Physics 2011-06-07 Tao Yan , Fengli Yan

Quantum key distribution allows for the generation of a secret key between distant parties connected by a quantum channel such as optical fibre or free space. Unfortunately, the rate of generation of a secret key by direct transmission is…

Quantum secret-sharing protocols involving N partners (NQSS) are key distribution protocols in which Alice encodes her key into $N-1$ qubits, in such a way that all the other partners must cooperate in order to retrieve the key. On these…

Quantum Physics · Physics 2009-11-07 Valerio Scarani , Nicolas Gisin