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We report a continuous variable key distribution system that achieves a final secure key rate of 3.45 kb/sec over a distance of 24.2 km of optical fiber. The protocol uses discrete signaling and post-selection to improve reconciliation…

Quantum Physics · Physics 2009-10-07 Quyen Dinh Xuan , Zheshen Zhang , Paul L. Voss

We designed high-efficiency error correcting codes allowing to extract an errorless secret key in a continuous-variable quantum key distribution protocol using a Gaussian modulation of coherent states and a homodyne detection. These codes…

Quantum Physics · Physics 2015-05-30 Paul Jouguet , Sébastien Kunz-Jacques , Anthony Leverrier

Quantum key distribution provides a promising solution for sharing secure keys between two distant parties with unconditional security. Nevertheless, quantum key distribution is still severely threatened by the imperfections of devices. In…

Quantum Physics · Physics 2023-08-22 Shan-Feng Shao , Xiao-Yu Cao , Yuan-Mei Xie , Jie Gu , Wen-Bo Liu , Yao Fu , Hua-Lei Yin , Zeng-Bing Chen

Quantum key distribution allows remote parties to generate information-theoretic secure keys. The bottleneck throttling its real-life applications lies in the limited communication distance and key generation speed, due to the fact that the…

Quantum Physics · Physics 2019-04-24 Xiongfeng Ma , Pei Zeng , Hongyi Zhou

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

The quantum key distribution (QKD), guaranteed by the principle of quantum physics, is a promising solution for future secure information and communication technology. However, device imperfections compromise the security of real-life QKD…

Quantum Physics · Physics 2022-09-14 Ye Chen , Chunfeng Huang , Zihao Chen , Wenjie He , Chengxian Zhang , Shihai Sun , Kejin Wei

We prove the unconditional security of a quantum key distribution protocol in which bit values are encoded in the phase of a weak coherent-state pulse relative to a strong reference pulse. In contrast to implementations in which a weak…

Quantum Physics · Physics 2009-11-10 Masato Koashi

Correlation between different pulses is a nettlesome problem in quantum key distribution (QKD). All existing solutions for this problem need to characterize the strength of the correlation, which may reduce the security of QKD to an…

Quantum key distribution (QKD) theoretically provides unconditional security between remote parties. However, guaranteeing practical security through device characterisation alone is challenging in real-world implementations due to the…

Quantum Physics · Physics 2025-04-29 Hao Dong , Cong Jiang , Di Ma , Chi Zhang , Jia Huang , Hao Li , Li-Xing You , Yang Liu , Xiang-Bin Wang , Qiang Zhang , Jian-Wei Pan

We investigate the security bounds of quantum cryptographic protocols using $d$-level systems. In particular, we focus on schemes that use two mutually unbiased bases, thus extending the BB84 quantum key distribution scheme to higher…

Quantum Physics · Physics 2007-05-23 Georgios M. Nikolopoulos , Gernot Alber

Continuous-variable quantum key distribution (CV-QKD) has emerged as a promising approach for secure quantum communication, offering advantages such as high key generation rates, compatibility with standard telecommunication infrastructure,…

We investigate a general class of quantum key distribution (QKD) protocols using one-way classical communication. We show that full security can be proven by considering only collective attacks. We derive computable lower and upper bounds…

Quantum Physics · Physics 2009-11-10 B. Kraus , N. Gisin , R. Renner

For quantum key distribution (QKD) using spontaneous parametric-down-conversion sources (SPDCSs), the passive decoy-state protocol has been proved to be efficiently close to the theoretical limit of an infinite decoy-state protocol. In this…

Quantum Physics · Physics 2014-06-03 Chun Zhou , Wan-su Bao , Hong-wei Li , Yang Wang , Yuan Li , Zhen-qiang Yin , Wei Chen , Zheng-fu Han

Secret sharing allows a trusted party (the dealer) to distribute a secret to a group of players, who can only access the secret cooperatively. Quantum secret sharing (QSS) protocols could provide unconditional security based on fundamental…

Quantum Physics · Physics 2019-09-04 Warren P. Grice , Bing Qi

Differential phase shift quantum key distribution systems have a high potential for achieving high speed key generation. However, its unconditional security proof is still missing, even though it has been proposed for many years. Here, we…

Quantum Physics · Physics 2008-10-28 Yi-Bo Zhao , Chi-Hang Fred Fung , Zheng-Fu Han , Guang-Can Guo

In this paper we report a continuous-variable quantum key distribution protocol using multimode coherent states generated on subcarrier frequencies of the optical spectrum. To detect the quadrature components of bosonic field we propose a…

The security of two-state quantum key distribution against individual attack is estimated when the channel has losses and noises. We assume that Alice and Bob use two nonorthogonal single-photon polarization states. To make our analysis…

Quantum Physics · Physics 2009-11-07 Kiyoshi Tamaki , Masato Koashi , Nobuyuki Imoto

Unconditional security proofs of the Bennett-Brassard protocol of quantum key distribution have been obtained recently. These proofs cover also practical implementations that utilize weak coherent pulses in the four signal polarizations.…

Quantum Physics · Physics 2009-11-10 Marcos Curty , Norbert Lütkenhaus

The lists of bits processed in quantum key distribution are necessarily of finite length. The need for finite-key unconditional security bounds has been recognized long ago, but the theoretical tools have become available only very…

Quantum Physics · Physics 2015-05-13 Raymond Y. Q. Cai , Valerio Scarani

In this paper we present quantum key distribution protocol that, instead of single qubits, uses mesoscopic coherent states of light $|\alpha\rangle$ to encode bit values of a randomly generated key. Given the reference value…

Quantum Physics · Physics 2017-05-04 G. A. Barbosa , J. van de Graaf , P. Mateus , N. Paunković