scholarly journals Path-encoded high-dimensional quantum communication over a 2-km multicore fiber

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Beatrice Da Lio ◽  
Daniele Cozzolino ◽  
Nicola Biagi ◽  
Yunhong Ding ◽  
Karsten Rottwitt ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Quantum Communication ◽  
Error Rates ◽  
Quantum States ◽  
High Dimensional ◽  
Secret Key ◽  
System A ◽  
Reliable Transmission ◽  
Multicore Fiber ◽  
Interferometric Detection

AbstractQuantum key distribution (QKD) protocols based on high-dimensional quantum states have shown the route to increase the key rate generation while benefiting of enhanced error tolerance, thus overcoming the limitations of two-dimensional QKD protocols. Nonetheless, the reliable transmission through fiber links of high-dimensional quantum states remains an open challenge that must be addressed to boost their application. Here, we demonstrate the reliable transmission over a 2-km-long multicore fiber of path-encoded high-dimensional quantum states. Leveraging on a phase-locked loop system, a stable interferometric detection is guaranteed, allowing for low error rates and the generation of 6.3 Mbit/s of a secret key rate.

scholarly journals Efficient High-Dimensional Quantum Key Distribution with Hybrid Encoding

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 80 ◽  
Author(s):  
Yonggi Jo ◽  
Hee Park ◽  
Seung-Woo Lee ◽  
Wonmin Son
Keyword(s):  
Angular Momentum ◽  
Quantum Key Distribution ◽  
Degrees Of Freedom ◽  
Single Photon ◽  
Key Distribution ◽  
Quantum States ◽  
High Dimensional ◽  
Practical Implementation ◽  
Secret Key ◽  
Optical Elements

We propose a schematic setup of quantum key distribution (QKD) with an improved secret key rate based on high-dimensional quantum states. Two degrees-of-freedom of a single photon, orbital angular momentum modes, and multi-path modes, are used to encode secret key information. Its practical implementation consists of optical elements that are within the reach of current technologies such as a multiport interferometer. We show that the proposed feasible protocol has improved the secret key rate with much sophistication compared to the previous 2-dimensional protocol known as the detector-device-independent QKD.

Quantum communication scheme with freely selectable users

2021 ◽  
pp. 2150156
Author(s):  
Tianqi Dou ◽  
Hongwei Liu ◽  
Jipeng Wang ◽  
Zhenhua Li ◽  
Wenxiu Qu ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Quantum Communication ◽  
Information Science ◽  
Quantum Secret Sharing ◽  
Key Distribution ◽  
Communication Process ◽  
Secret Key ◽  
Quantum Information Science ◽  
Transmission Distance ◽  
Communication Scheme

Quantum communication plays an important role in quantum information science due to its unconditional security. In practical implementations, the users of each communication vary with the transmitted information, and hence not all users are required to participate in each communication round. Therefore, improving the flexibility and efficiency of the actual communication process is highly demanded. Here, we propose a theoretical quantum communication scheme that realizes secret key distribution for both the two-party quantum key distribution (QKD) and multi-party quantum secret sharing (QSS) modes. The sender, Alice, can freely select one or more users to share keys among all users, and nonactive users will not participate in the process of secret key sharing. Numerical simulations show the superiority of the proposed scheme in transmission distance and secure key rate. Consequently, the proposed scheme is valuable for secure quantum communication network scenarios.

Information reconciliation for QKD

2011 ◽  
Vol 11 (3&4) ◽  
pp. 226-238
Author(s):  
David Elkouss ◽  
Jesus Martinez-Mateo ◽  
Vicente Martin
Keyword(s):  
Quantum Key Distribution ◽  
Key Agreement ◽  
Information Leakage ◽  
Error Rates ◽  
Parity Check ◽  
Random String ◽  
Secret Key ◽  
Information Reconciliation ◽  
Low Density Parity Check ◽  
Secret Key Agreement

Quantum key distribution (QKD) relies on quantum and classical procedures in order to achieve the growing of a secret random string ---the key--- known only to the two parties executing the protocol. Limited intrinsic efficiency of the protocol, imperfect devices and eavesdropping produce errors and information leakage from which the set of measured signals ---the raw key--- must be stripped in order to distill a final, information theoretically secure, key. The key distillation process is a classical one in which basis reconciliation, error correction and privacy amplification protocols are applied to the raw key. This cleaning process is known as information reconciliation and must be done in a fast and efficient way to avoid cramping the performance of the QKD system. Brassard and Salvail proposed a very simple and elegant protocol to reconcile keys in the secret-key agreement context, known as \textit{Cascade}, that has become the de-facto standard for all QKD practical implementations. However, it is highly interactive, requiring many communications between the legitimate parties and its efficiency is not optimal, imposing an early limit to the maximum tolerable error rate. In this paper we describe a low-density parity-check reconciliation protocol that improves significantly on these problems. The protocol exhibits better efficiency and limits the number of uses of the communications channel. It is also able to adapt to different error rates while remaining efficient, thus reaching longer distances or higher secure key rate for a given QKD system.

AUTHENTICATED QUANTUM KEY DISTRIBUTION WITHOUT CLASSICAL COMMUNICATION

2007 ◽  
Vol 17 (03) ◽  
pp. 323-335 ◽  
Author(s):  
NAYA NAGY ◽  
SELIM G. AKL
Keyword(s):  
Quantum Channel ◽  
Quantum Key Distribution ◽  
Communication Channel ◽  
Quantum Communication ◽  
Key Distribution ◽  
Secret Key ◽  
Classical Communication ◽  
Quantum Communication Channel ◽  
High Security ◽  
Public Keys

The aim of quantum key distribution protocols is to establish a secret key among two parties with high security confidence. Such algorithms generally require a quantum channel and an authenticated classical channel. This paper presents a totally new perception of communication in such protocols. The quantum communication alone satisfies all needs of array communication between the two parties. Even so, the quantum communication channel does not need to be protected or authenticated whatsoever. As such, our algorithm is a purely quantum key distribution algorithm. The only certain identification of the two parties is through public keys.

scholarly journals Quantum process tomography of a high-dimensional quantum communication channel

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 138 ◽  
Author(s):  
Frédéric Bouchard ◽  
Felix Hufnagel ◽  
Dominik Koutný ◽  
Aazad Abbas ◽  
Alicia Sit ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Quantum Communication ◽  
Communication Channels ◽  
Key Distribution ◽  
Coarse Grained ◽  
High Dimensional ◽  
Quantum Process ◽  
Quantum Process Tomography ◽  
Process Tomography

The characterization of quantum processes, e.g. communication channels, is an essential ingredient for establishing quantum information systems. For quantum key distribution protocols, the amount of overall noise in the channel determines the rate at which secret bits are distributed between authorized partners. In particular, tomographic protocols allow for the full reconstruction, and thus characterization, of the channel. Here, we perform quantum process tomography of high-dimensional quantum communication channels with dimensions ranging from 2 to 5. We can thus explicitly demonstrate the effect of an eavesdropper performing an optimal cloning attack or an intercept-resend attack during a quantum cryptographic protocol. Moreover, our study shows that quantum process tomography enables a more detailed understanding of the channel conditions compared to a coarse-grained measure, such as quantum bit error rates. This full characterization technique allows us to optimize the performance of quantum key distribution under asymmetric experimental conditions, which is particularly useful when considering high-dimensional encoding schemes.

scholarly journals Stable Transmission of High-Dimensional Quantum States Over a 2-km Multicore Fiber

2020 ◽  
Vol 26 (4) ◽  
pp. 1-8 ◽  
Author(s):  
Beatrice Da Lio ◽  
Leif Katsuo Oxenlowe ◽  
Davide Bacco ◽  
Daniele Cozzolino ◽  
Nicola Biagi ◽  
...  
Keyword(s):  
Quantum States ◽  
High Dimensional ◽  
Multicore Fiber ◽  
Stable Transmission

scholarly journals Photonic integrated chip enabling orbital angular momentum multiplexing for quantum communication

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mujtaba Zahidy ◽  
Yaoxin Liu ◽  
Daniele Cozzolino ◽  
Yunhong Ding ◽  
Toshio Morioka ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Quantum Key Distribution ◽  
Information Technologies ◽  
Quantum Communication ◽  
Photonic Devices ◽  
Secret Key ◽  
Data Capacity ◽  
Core Fiber ◽  
Ring Core

Abstract Light carrying orbital angular momentum constitutes an important resource for both classical and quantum information technologies. Its inherently unbounded nature can be exploited to generate high-dimensional quantum states or for channel multiplexing in classical and quantum communication in order to significantly boost the data capacity and the secret key rate, respectively. While the big potentials of light owning orbital angular momentum have been widely ascertained, its technological deployment is still limited by the difficulties deriving from the fabrication of integrated and scalable photonic devices able to generate and manipulate it. Here, we present a photonic integrated chip able to excite orbital angular momentum modes in an 800 m long ring-core fiber, allowing us to perform parallel quantum key distribution using two and three different modes simultaneously. The experiment sets the first steps towards quantum orbital angular momentum division multiplexing enabled by a compact and light-weight silicon chip, and further pushes the development of integrated scalable devices supporting orbital angular momentum modes.

scholarly journals Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States

2007 ◽  
Vol 14 (01) ◽  
pp. 69-80 ◽  
Author(s):  
C. Rodó ◽  
O. Romero-Isart ◽  
K. Eckert ◽  
A. Sanpera
Keyword(s):  
Quantum Key Distribution ◽  
Figure Of Merit ◽  
Degrees Of Freedom ◽  
Key Distribution ◽  
Quantum States ◽  
Entangled States ◽  
Secret Key ◽  
Gaussian States ◽  
Quantum Strategies ◽  
Specific Quantum

Quantum key distribution (QKD) refers to specific quantum strategies which permit the secure distribution of a secret key between two parties that wish to communicate secretly. Quantum cryptography has proven unconditionally secure in ideal scenarios and has been successfully implemented using quantum states with finite (discrete) as well as infinite (continuous) degrees of freedom. Here, we analyze the efficiency of QKD protocols that use as a resource entangled gaussian states and gaussian operations only. In this framework, it has already been shown that QKD is possible [1] but the issue of its efficiency has not been considered. We propose a figure of merit (the efficiency E) to quantify the number of classical correlated bits that can be used to distill a key from a sample of N entangled states. We relate the efficiency of the protocol to the entanglement and purity of the states shared between the parties.

scholarly journals CLASSICAL CORRELATION IN QUANTUM DIALOGUE

2008 ◽  
Vol 06 (02) ◽  
pp. 325-329 ◽  
Author(s):  
YONG-GANG TAN ◽  
QING-YU CAI
Keyword(s):  
Quantum Mechanics ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Quantum States ◽  
Quantum Dialogue ◽  
Secret Message ◽  
Secret Key ◽  
Post Processing ◽  
Classical Correlation ◽  
Processing Procedure

Classical communications are used in the post-processing procedure of quantum key distribution. Since the security of quantum key distribution is based on the principles of quantum mechanics, intuitively, the secret key can only be derived from the quantum states. We find that classical communications are incorrectly used in the so-called quantum dialogue type protocols. In these protocols, public communications are used to transmit secret messages. Our calculations show that half of Alice's and Bob's secret message is leaked through the classical channel. By applying the Holevo bound, we can see that the quantum efficiency claimed in the quantum dialogue type of protocols is not achievable.

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