302 research outputs found
A method for computing Lucas sequences
AbstractMost of public-key cryptosystems rely on one-way functions, which can be used to encrypt and sign messages. Their encryption and signature operations are based on the computation of exponentiation. Recently, some public-key cryptosystems are proposed and based on Lucas functions, and the Lucas sequences are performed as S = V(d)modN. In this paper, we will transform the concept of addition chains for computing the exponentiation evaluations to the Lucas chains for computing the Lucas sequences. Theoretically, the shorter Lucas chain for d is generated, the less computation time for evaluating the value V(d) is required. Therefore, we proposed a heuristic algorithm for evaluating a shorter Lucas chain and then use it to compute the Lucas sequence with less modular multiplications
Modified Autonomous Key Management Scheme with Reduced Communication/Computation Costs in MANET
The growing applications of mobile ad hoc networks (MANETs) have made related security issues much more important. B. Zhu et al. proposed a key management scheme using Shamir's secret sharing scheme to construct an Autonomous Key Management (AKM) hierarchy structure. However, Shamir's secret sharing in AKM to control key hierarchy incurs high message transmission costs. This paper modifies the secret sharing scheme and applies it to AKM to reduce communication and computation costs
Weakness of shim¡¦s New ID-based tripartite multiple-key agreement protocol
In this article we show that Shim¡¦s new ID-based tripartite multiple-key agreement protocol still suffers from the impersonation attack, a malicious user can launch an impersonation attack on their protocol
Speeding Up RSA Encryption Using GPU Parallelization
Abstract-Due to the ever-increasing computing capability of high performance computers today, in order to protect encrypted data from being cracked, the bit number used in RSA, a common and practicable public-key cryptosystem, is also getting longer, resulting in increasing operation time spent in executing the RSA algorithm. We also note that while the development of CPU has reached limits, the graphics processing unit (GPU), a highly parallel programmable processor, has become an integral part of today's mainstream computing systems. Therefore, it is a savvy choice to take advantage of GPU computing to accelerate computation of the RSA algorithm and enhance its applicability as well. After analyzing the RSA algorithm, we find that big number operations consume most parts of computing resources. As the benefit acquired from combining Montgomery with GPU-based parallel methods is not high enough, we further introduce the Fourier transform and Newton's method to design a new parallel algorithm to accelerate the computation of big numbers
Decentralized Base-Graph Routing for the Quantum Internet
Quantum repeater networks are a fundamental of any future quantum Internet
and long-distance quantum communications. The entangled quantum nodes can
communicate through several different levels of entanglement, leading to a
heterogeneous, multi-level network structure. The level of entanglement between
the quantum nodes determines the hop distance and the probability of the
existence of an entangled link in the network. Here, we define a decentralized
routing for entangled quantum networks. The proposed method allows an efficient
routing to find the shortest paths in entangled quantum networks by using only
local knowledge of the quantum nodes. We give bounds on the maximum value of
the total number of entangled links of a path. The proposed scheme can be
directly applied in practical quantum communications and quantum networking
scenarios.Comment: 13 pages, Journal-ref: Phys. Rev.
The risk of false inclusion of a relative in parentage testing – an in silico population study
Aim To investigate the potential of false inclusion of a
close genetic relative in paternity testing by using computer
generated families.
Methods 10 000 computer-simulated families over three
generations were generated based on genotypes using 15
short tandem repeat loci. These data were used in assessing
the probability of inclusion or exclusion of paternity
when the father is actually a sibling, grandparent, uncle,
half sibling, cousin, or a random male. Further, we considered
a duo case where the mother’s DNA type was not
available and a trio case including the mother’s profile.
Results The data showed that the duo scenario had the
highest and lowest false inclusion rates when considering
a sibling (19.03 ± 0.77%) and a cousin (0.51 ± 0.14%) as
the father, respectively; and the rate when considering a
random male was much lower (0.04 ± 0.04%). The situation
altered slightly with a trio case where the highest rate
(0.56 ± 0.15%) occurred when a paternal uncle was considered
as the father, and the lowest rate (0.03 ± 0.03%) occurred
when a cousin was considered as the father. We also
report on the distribution of the numbers for non-conformity
(non-matching loci) where the father is a close genetic
relative.
Conclusions The results highlight the risk of false inclusion
in parentage testing. These data provide a valuable
reference when incorporating either a mutation in the father’s
DNA type or if a close relative is included as being
the father; particularly when there are varying numbers of
non-matching loci
A novel strategy for sibship determination in trio sibling model
Aim To use a virtually simulated population, generated
from published allele frequencies based on 15 short tandem
repeats (STR), to evaluate the efficacy of trio sibship
testing and sibling assignment for forensic purposes.
Methods Virtual populations were generated using 15 STR
loci to create a large number of related and unrelated genotypes
(10 000 trio combinations). Using these virtual populations,
the probability of related and unrelated profiles
can be compared to determine the chance of inclusions
of being siblings if they are true siblings and the chance of
inclusion if they are unrelated. Two specific relationships
were tested – two reference siblings were compared to a
third true sibling (3S trio, sibling trio) and two reference siblings
were compared to an unrelated individual (2S1U trio,
non-sibling trio).
Results When the likelihood ratio was greater than 1,
99.87% of siblings in the 3S trio population were considered
as siblings (sensitivity); 99.88% of non-siblings in the
2S1U trio population were considered as non-siblings
(specificity); 99.9% of both populations were identified correctly
as siblings and non-siblings; and the accuracy of the
test was 99.88%.
Conclusions The high sensitivity and specificity figures
when using two known siblings compared to a putative
sibling are significantly greater than when using only one
known relative. The data also support the use of increasing
number of loci allowing for greater confidence in genetic
identification. The system established in this study could
be used as the model for evaluating and simulating the
cases with multiple relatives
Clonal dissemination of the multi-drug resistant Salmonella enterica serovar Braenderup, but not the serovar Bareilly, of prevalent serogroup C1 Salmonella from Taiwan
<p>Abstract</p> <p>Background</p> <p>Nontyphoidal <it>Salmonella </it>is the main cause of human salmonellosis. In order to study the prevalent serogroups and serovars of clinical isolates in Taiwan, 8931 <it>Salmonellae </it>isolates were collected from 19 medical centers and district hospitals throughout the country from 2004 to 2007. The pulsed-field eletrophoresis types (PFGE) and antibiotic resistance profiles of <it>Salmonella enterica </it>serovars Bareilly (<it>S</it>. Bareilly) and Braenderup (<it>S</it>. Braenderup) were compared, and multi-drug resistance (MDR) plasmids were characterized.</p> <p>Results</p> <p>Over 95% of human salmonellosis in Taiwan was caused by five <it>Salmonella </it>serogroups: B, C1, C2-C3, D1, and E1. <it>S</it>. Typhymurium, <it>S</it>. Enteritidis, <it>S</it>. Stanley and <it>S</it>. Newport were the four most prevalent serovars, accounting for about 64% of isolates. While only one or two major serovars from four of the most prevalent serogroups were represented, four predominant serovars were found in serogroup C1 <it>Salmonellae</it>. The prevalence was decreasing for <it>S</it>. Choleraeuis and <it>S</it>. Braenderup, and S. Virchow and increasing for <it>S</it>. Bareilly. <it>S</it>. Braenderup mainly caused gastroenteritis in children; in contrast, <it>S</it>. Bareiley infected children and elderly people. Both serovars differed by <it>Xba</it>I-PFGE patterns. Almost all <it>S</it>. Bareilly isolates were susceptible to antibiotics of interest, while all lacked plasmids and belonged to one clone. Two distinct major clones in <it>S</it>. Braenderup were cluster A, mainly including MDR isolates with large MDR plasmid from North Taiwan, and cluster B, mainly containing susceptible isolates without R plasmid from South Taiwan. In cluster A, there were two types of conjugative R plasmids with sizes ranging from 75 to 130 kb. Type 1 plasmids consisted of replicons F1A/F1B, <it>bla</it><sub>TEM</sub>, IS<it>26</it>, and a class 1 integron with the genes <it>dfrA12</it>-<it>orfF</it>-<it>aadA2-qacE</it>Δ1-<it>sulI</it>. Type 2 plasmids belonged to incompatibility group Inc<it>I</it>, contained <it>tnpA</it>-<it>bla</it><sub>CMY-2</sub>-<it>blc</it>-<it>sugE </it>genetic structures and lacked both IS<it>26 </it>and class 1 integrons. Although type 2 plasmids showed higher conjugation capability, type 1 plasmids were the predominant plasmid.</p> <p>Conclusions</p> <p>Serogroups B, C1, C2-C3, D1, and E1 of <it>Salmonella </it>caused over 95% of human salmonellosis. Two prevalent serovars within serogroup C1, <it>S</it>. Bareilly and cluster B of S. Braenderup, were clonal and drug-susceptible. However, cluster A of <it>S</it>. Braenderup was MDR and probably derived from susceptible isolates by acquiring one of two distinct conjugative R plasmids.</p
The optimal pulse pressures for healthy adults with different ages and sexes correlate with cardiovascular health metrics
BackgroundPulse pressure (PP) may play a role in the development of cardiovascular disease, and the optimal PP for different ages and sexes is unknown. In a prospective cohort, we studied subjects with favorable cardiovascular health (CVH), proposed the mean PP as the optimal PP values, and demonstrated its relationship with healthy lifestyles.Methods and resultsBetween 1996 and 2016, a total of 162,636 participants (aged 20 years or above; mean age 34.9 years; 26.4% male subjects; meeting criteria for favorable health) were recruited for a medical examination program. PP in male subjects was 45.6 ± 9.4 mmHg and increased after the age of 50 years. PP in female subjects was 41.8 ± 9.5 mmHg and increased after the age of 40 years, exceeding that of male subjects after the age of 50 years. Except for female subjects with a PP of 40–70 mmHg, PP increase correlates with both systolic blood pressure (BP) increase and diastolic BP decrease. Individuals with mean PP values are more likely to meet health metrics, including body mass index (BMI) <25 kg/m2 (chi-squared = 9.35, p<0.01 in male subjects; chi-squared = 208.79, p < 0.001 in female subjects) and BP <120/80 mmHg (chi-squared =1,300, p < 0.001 in male subjects; chi-squared =11,000, p < 0.001 in female subjects). We propose a health score (Hscore) based on the sum of five metrics (BP, BMI, being physically active, non-smoking, and healthy diet), which significantly correlates with the optimal PP.ConclusionThe mean PP (within ±1 standard deviation) could be proposed as the optimal PP in the adult population with favorable CVH. The relationship between health metrics and the optimal PP based on age and sex was further demonstrated to validate the Hscore
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