63 research outputs found
Advantages of Asynchronous Measurement-Device-Independent Quantum Key Distribution in Intercity Networks
The new variant of measurement-device-independent quantum key distribution
(MDI-QKD), called asynchronous MDI-QKD or mode-pairing MDI-QKD, offers similar
repeater-like rate-loss scaling but has the advantage of simple technology
implementation by exploiting an innovative post-measurement pairing technique.
We herein present an evaluation of the practical aspects of decoy-state
asynchronous MDI-QKD. To determine its effectiveness, we analyze the optimal
method of decoy-state calculation and examine the impact of asymmetrical
channels and multi-user networks. Our simulations show that, under realistic
conditions, aynchronous MDI-QKD can furnish the highest key rate with MDI
security as compared to other QKD protocols over distances ranging from 50 km
to 480 km. At fiber distances of 50 km and 100 km, the key rates attain 6.02
Mbps and 2.29 Mbps respectively, which are sufficient to facilitate real-time
one-time-pad video encryption. Our findings indicate that experimental
implementation of asynchronous MDI-QKD in intercity networks can be both
practical and efficient
Experimental quantum secure network with digital signatures and encryption
Cryptography promises four information security objectives, namely,
confidentiality, integrity, authenticity, and non-repudiation, to support
trillions of transactions annually in the digital economy. Efficient digital
signatures, ensuring the integrity, authenticity, and non-repudiation of data
with information-theoretical security are highly urgent and intractable open
problems in cryptography. Here, we propose a protocol of high-efficiency
quantum digital signatures using secret sharing, one-time universal
hashing, and the one-time pad. We just need to use a 384-bit key to sign
documents of up to lengths with a security bound of . If
one-megabit document is signed, the signature efficiency is improved by more
than times compared with previous quantum digital signature protocols.
Furthermore, we build the first all-in-one quantum secure network integrating
information-theoretically secure communication, digital signatures, secret
sharing, and conference key agreement and experimentally demonstrate this
signature efficiency advantage. Our work completes the cryptography toolbox of
the four information security objectives.Comment: 19 pages, 7 figures, 4 tables. Quantum digital signatures and quantum
private communication maintain a consistent level of practicalit
Simple security proof of coherent-one-way quantum key distribution
Coherent-one-way quantum key distribution (COW-QKD), which requires a simple
experimental setup and has the ability to withstand photon-number-splitting
attacks, has been not only experimentally implemented but also commercially
applied. However, recent studies have shown that the current COW-QKD system is
insecure and can only distribute secret keys safely within 20 km of the optical
fiber length. In this study, we propose a practical implementation of COW-QKD
by adding a two-pulse vacuum state as a new decoy sequence. This proposal
maintains the original experimental setup as well as the simplicity of its
implementation. Utilizing detailed observations on the monitoring line to
provide an analytical upper bound on the phase error rate, we provide a
high-performance COW-QKD asymptotically secure against coherent attacks. This
ensures the availability of COW-QKD within 100 km and establishes theoretical
foundations for further applications.Comment: 8 pages, 5 figures, 1 tabl
Beating the fault-tolerance bound and security loopholes for Byzantine agreement with a quantum solution
Byzantine agreement, the underlying core of blockchain, aims to make every
node in a decentralized network reach consensus. Classical Byzantine agreements
unavoidably face two major problems. One is fault-tolerance bound, which
means that the system to tolerate malicious players requires at least
players. The other is the security loopholes from its classical
cryptography methods. Here, we propose a strict quantum Byzantine agreement
with unconditional security to break this bound with nearly fault
tolerance due to multiparty correlation provided by quantum digital signatures.
Our work strictly obeys the original Byzantine conditions and can be extended
to any number of players without requirements for multiparticle entanglement.
We experimentally demonstrate three-party and five-party quantum consensus for
a digital ledger. Our work indicates the quantum advantage in terms of
consensus problems and suggests an important avenue for quantum blockchain and
quantum consensus networks.Comment: 22 pages, 10 figures. All comments are welcome
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
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An open science resource for establishing reliability and reproducibility in functional connectomics
Efforts to identify meaningful functional imaging-based biomarkers are limited by the ability to reliably characterize inter-individual differences in human brain function. Although a growing number of connectomics-based measures are reported to have moderate to high test-retest reliability, the variability in data acquisition, experimental designs, and analytic methods precludes the ability to generalize results. The Consortium for Reliability and Reproducibility (CoRR) is working to address this challenge and establish test-retest reliability as a minimum standard for methods development in functional connectomics. Specifically, CoRR has aggregated 1,629 typical individualsβ resting state fMRI (rfMRI) data (5,093 rfMRI scans) from 18 international sites, and is openly sharing them via the International Data-sharing Neuroimaging Initiative (INDI). To allow researchers to generate various estimates of reliability and reproducibility, a variety of data acquisition procedures and experimental designs are included. Similarly, to enable users to assess the impact of commonly encountered artifacts (for example, motion) on characterizations of inter-individual variation, datasets of varying quality are included
IterCluster: a barcode clustering algorithm for long fragment read analysis
Recent advances in long fragment read (LFR, also known as linked-read technologies or read-cloud) technologies, such as single tube long fragment reads (stLFR), 10X Genomics Chromium reads, and TruSeq synthetic long-reads, have enabled efficient haplotyping and genome assembly. However, in the case of stLFR and 10X Genomics Chromium reads, the long fragments of a genome are covered sparsely by reads in each barcode and most barcodes are contained in multiple long fragments from different regions, which results in inefficient assembly when using long-range information. Thus, methods to address these shortcomings are vital for capitalizing on the additional information obtained using these technologies. We therefore designed IterCluster, a novel, alignment-free clustering algorithm that can cluster barcodes from the same target region of a genome, using -mer frequency-based features and a Markov Cluster (MCL) approach to identify enough reads in a target region of a genome to ensure sufficient target genome sequence depth. The IterCluster method was validated using BGI stLFR and 10X Genomics chromium reads datasets. IterCluster had a higher precision and recall rate on BGI stLFR data compared to 10X Genomics Chromium read data. In addition, we demonstrated how IterCluster improves the de novo assembly results when using a divide-and-conquer strategy on a human genome data set (scaffold/contig N50 = 13.2 kbp/7.1 kbp vs. 17.1 kbp/11.9 kbp before and after IterCluster, respectively). IterCluster provides a new way for determining LFR barcode enrichment and a novel approach for de novo assembly using LFR data. IterCluster is OpenSource and available on https://github.com/JianCong-WENG/IterCluster
Scalable High-Rate Twin-Field Quantum Key Distribution Networks without Constraint of Probability and Intensity
There have been several recent advancements in the field of long-distance
point-to-point twin-field quantum key distribution (TFQKD) protocols, with an
ultimate objective to build a large scalable quantum network for numerous
users. Currently, fundamental limitations still exist for the implementation of
a practical TFQKD network, including the strict constraint regarding intensity
and probability for sending-or-not-sending type protocols and the low tolerance
of large interference errors for phase-matching type protocols. Here, we
propose a two-photon TFQKD protocol to overcome these issues simultaneously and
introduce a cost-effective solution to construct a real TFQKD network, under
which each node with fixed system parameters can dynamically switch different
attenuation links while achieving good performance in long-distance
transmission. For a four-user network, simulation results indicate that the key
rates of our protocol for all six links can either exceed or approach the
secret key capacity; however, four of them could not extract the key rate if
using sending-or-not-sending type protocols. We anticipate that our proposed
method can facilitate new practical and efficient TFQKD networks in the future.Comment: 15 pages, 5 figures, 3 table
Experimental quantum secret sharing based on phase encoding of coherent states
Quantum secret sharing (QSS) is one of the basic communication primitives in
future quantum networks which addresses part of the basic cryptographic tasks
of multiparty communication and computation. Nevertheless, it is a challenge to
provide a practical QSS protocol with security against general attacks. A QSS
protocol that balances security and practicality is still lacking. Here, we
propose a QSS protocol with simple phase encoding of coherent states among
three parties. Removing the requirement of impractical entangled resources and
the need for phase randomization, our protocol can be implemented with
accessible technology. We provide the finite-key analysis against coherent
attacks and implement a proof-of-principle experiment to demonstrate our
scheme's feasibility. Our scheme achieves a key rate of 85.3 bps under a 35 dB
channel loss. Combined with security against general attacks and accessible
technology, our protocol is a promising candidate for practical multiparty
quantum communication networks.Comment: 10 pages, 5 figures, 3 tables, accepted by Sci. China-Phys. Mech.
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