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We propose a high-efficiency three-party quantum key agreement protocol, by utilizing two-photon polarization-entangled Bell states and a few single-photon polarization states as the information carriers, and we use the quantum dense coding…

Quantum Physics · Physics 2019-06-26 Wan-Ting He , Jun Wang , Tian-Tian Zhang , Faris Alzahrani , Aatef Hobiny , Tasawar Hayat , Fu-Guo Deng

In state-of-the-art quantum key distribution (QKD) systems, the main limiting factor in increasing the key generation rate is the timing resolution in detecting photons. Here, we present and experimentally demonstrate a strategy to overcome…

Quantum Physics · Physics 2021-07-29 Johannes Pseiner , Lukas Achatz , Lukas Bulla , Martin Bohmann , Rupert Ursin

Random generation and confidential distribution of cryptographic keys are fundamental building blocks of secure communication. Using quantum states in which the transmitted quantum bit is entangled with a stationary memory quantum bit…

Quantum Physics · Physics 2021-11-30 Pascal Kobel , Ralf A. Berner , Michael Köhl

Quantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum…

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

We report the security analysis of time-coding quantum key distribution protocols. The protocols make use of coherent single-photon pulses. The key is encoded in the photon time-detection. The use of coherent superposition of states allows…

Quantum Physics · Physics 2011-09-29 Thierry Debuisschert , Simon Fossier

The coding space in quantum communication could be expanded to high-dimensional space by using orbital angular momentum (OAM) states of photons, as both the capacity of the channel and security are enhanced. Here we present a novel approach…

Quantum Physics · Physics 2021-01-01 Ziwen Pan , Jiarui Cai , Chuan Wang

We propose a new scheme for quantum key distribution using macroscopic non-classical pulses of light having of the order 10^6 photons per pulse. Sub-shot-noise quantum correlation between the two polarization modes in a pulse gives the…

Quantum Physics · Physics 2009-11-07 A. C. Funk , M. G. Raymer

We report on the first real-time implementation of a quantum key distribution (QKD) system using entangled photon pairs that are sent over two free-space optical telescope links. The entangled photon pairs are produced with a type-II…

Quantum Physics · Physics 2012-10-25 C. Erven , C. Couteau , R. Laflamme , G. Weihs

Channel loss seems to be the most severe limitation on the practical application of long distance quantum key distribution. The idea of twin-field quantum key distribution can improve the key rate from the linear scale of channel loss in…

We propose a multidimensional quantum information encoding approach based on temporal modulation of single photons, where the Hilbert space can be spanned by an in-principle infinite set of orthonormal temporal profiles. We analyze two…

Quantum Physics · Physics 2013-01-03 Alex Hayat , Xingxing Xing , Amir Feizpour , Aephraim M. Steinberg

We experimentally demonstrate a proposal [Phys. Rev. A 87, 052325 (2013)] of a scheme for robust distribution of polarization entangled photon pairs over collective noisy channels having the reciprocity. Although the scheme employs the…

Quantum Physics · Physics 2017-10-26 Rikizo Ikuta , Shota Nozaki , Takashi Yamamoto , Masato Koashi , Nobuyuki Imoto

Quantum key distribution, first proposed by Bennett and Brassard, provides a possible key distribution scheme whose security depends only on the quantum laws of physics. So far the protocol has been proved secure even under channel noise…

Quantum Physics · Physics 2007-05-23 Dominic Mayers , Andrew Yao

We propose a new quantum key distribution scheme that uses the blind polarization basis. In our scheme the sender and the receiver share key information by exchanging qubits with arbitrary polarization angles without basis reconciliation.…

Quantum Physics · Physics 2007-05-23 Won-Ho Kye , Chil-Min Kim , M. S. Kim , Young-Jai Park

We propose a quantum secret sharing protocol between multi-party ($m$ members in group 1) and multi-party ($n$ members in group 2) using a sequence of single photons. These single photons are used directly to encode classical information in…

Quantum Physics · Physics 2007-05-23 Feng-Li Yan , Ting Gao

Quantum key distribution (QKD) allows two spatially separated parties to securely generate a cryptographic key. The first QKD protocol, published by C. H. Bennett and G. Brassard in 1984 (BB84), describes how this is achieved by…

Quantum Physics · Physics 2009-03-13 Olli Ahonen

Two-qubit quantum codes have been suggested to obtain better efficiency and higher loss tolerance in quantum key distribution. Here, we propose a two-qubit quantum key distribution protocol based on a mixed basis consisting of two Bell…

Quantum Physics · Physics 2017-09-20 Mladen Pavicic , Oliver Benson , Andreas W. Schell , Janik Wolters

Noise and imperfection of realistic devices are major obstacles for implementing quantum cryptography. In particular birefringence in optical fibers leads to decoherence of qubits encoded in polarization of photon. We show how to overcome…

Quantum Physics · Physics 2009-11-10 J. -C. Boileau , R. Laflamme , M. Laforest , C. R. Myers

Quantum Key Distribution with the BB84 protocol has been shown to be unconditionally secure even using weak coherent pulses instead of single-photon signals. The distances that can be covered by these methods are limited due to the loss in…

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

We study the use of polar codes for both discrete and continuous variables Quantum Key Distribution (QKD). Although very large blocks must be used to obtain the efficiency required by quantum key distribution, and especially continuous…

Quantum Physics · Physics 2013-07-30 Paul Jouguet , Sébastien Kunz-Jacques