50 research outputs found
IoT-REX: A Secure Remote-Control System for IoT Devices from Centralized Multi-Designated Verifier Signatures
IoT technology has been developing rapidly, while at the same time, notorious
IoT malware such as Mirai is a severe and inherent threat. We believe it is
essential to consider systems that enable us to remotely control infected
devices in order to prevent or limit malicious behaviors of infected devices.
In this paper, we design a promising candidate for such remote-control systems,
called IoT-REX (REmote-Control System for IoT devices). IoT-REX allows a
systems manager to designate an arbitrary subset of all IoT devices in the
system and every device can confirm whether or not the device itself was
designated; if so, the device executes a command given from the systems
manager. Towards realizing IoT-REX, we introduce a novel cryptographic
primitive called centralized multi-designated verifier signatures (CMDVS).
Although CMDVS works under a restricted condition compared to conventional
MDVS, it is sufficient for realizing IoT-REX. We provide an efficient CMDVS
construction from any approximate membership query structures and digital
signatures, yielding compact communication sizes and efficient verification
procedures for IoT-REX. We then discuss the feasibility of IoT-REX through
cryptographic implementation of the CMDVS construction on a Raspberry Pi. Our
promising results demonstrate that the CMDVS construction can compress
communication size to about 30% and thus its resulting IoT-REX becomes three
times faster than a trivial construction over typical low-power wide area
networks with an IoT device. It is expected that IoT-REX can control 12,000
devices within a second.Comment: Updated as a whole. 26 page
JABBERWOCK: A Tool for WebAssembly Dataset Generation and Its Application to Malicious Website Detection
Machine learning is often used for malicious website detection, but an
approach incorporating WebAssembly as a feature has not been explored due to a
limited number of samples, to the best of our knowledge. In this paper, we
propose JABBERWOCK (JAvascript-Based Binary EncodeR by WebAssembly Optimization
paCKer), a tool to generate WebAssembly datasets in a pseudo fashion via
JavaScript. Loosely speaking, JABBERWOCK automatically gathers JavaScript code
in the real world, convert them into WebAssembly, and then outputs vectors of
the WebAssembly as samples for malicious website detection. We also conduct
experimental evaluations of JABBERWOCK in terms of the processing time for
dataset generation, comparison of the generated samples with actual WebAssembly
samples gathered from the Internet, and an application for malicious website
detection. Regarding the processing time, we show that JABBERWOCK can construct
a dataset in 4.5 seconds per sample for any number of samples. Next, comparing
10,000 samples output by JABBERWOCK with 168 gathered WebAssembly samples, we
believe that the generated samples by JABBERWOCK are similar to those in the
real world. We then show that JABBERWOCK can provide malicious website
detection with 99\% F1-score because JABBERWOCK makes a gap between benign and
malicious samples as the reason for the above high score. We also confirm that
JABBERWOCK can be combined with an existing malicious website detection tool to
improve F1-scores. JABBERWOCK is publicly available via GitHub
(https://github.com/c-chocolate/Jabberwock).Comment: Accepted in DCDS 2023 (co-located in DSN 2023
Prevalence and Risk Factors for Tuberculosis Infection among Hospital Workers in Hanoi, Viet Nam
BACKGROUND: Transmission of tuberculosis (TB) to health care workers (HCWs) is a global issue. Although effective infection control measures are expected to reduce nosocomial TB, HCWs' infection has not been assessed enough in TB high burden countries. We conducted a cross-sectional study to determine the prevalence of TB infection and its risk factors among HCWs in Hanoi, Viet Nam. METHODOLOGY/PRINCIPAL FINDINGS: A total of 300 HCWs including all staff members in a municipal TB referral hospital received an interferon-gamma release assay (IGRA), QuantiFERON-TB Gold In-Tube(TM), followed by one- and two-step tuberculin skin test (TST) and a questionnaire-based interview. Agreement between the tests was evaluated by kappa statistics. Risk factors for TB infection were analyzed using a logistic regression model. Among the participants aged from 20 to 58 years (median = 40), prevalence of TB infection estimated by IGRA, one- and two-step TST was 47.3%, 61.1% and 66.3% respectively. Although the levels of overall agreement between IGRA and TST were moderate, the degree of agreement was low in the group with BCG history (kappa = 0.29). Working in TB hospital was associated with twofold increase in odds of TB infection estimated by IGRA. Increased age, low educational level and the high body mass index also demonstrated high odds ratios of IGRA positivity. CONCLUSIONS/SIGNIFICANCE: Prevalence of TB infection estimated by either IGRA or TST is high among HCWs in the hospital environment for TB care in Viet Nam and an infection control program should be reinforced. In communities with heterogeneous history of BCG vaccination, IGRA seems to estimate TB infection more accurately than any other criteria using TST
Mobile DHHC palmitoylating enzyme mediates activity-sensitive synaptic targeting of PSD-95
Protein palmitoylation is the most common posttranslational lipid modification; its reversibility mediates protein shuttling between intracellular compartments. A large family of DHHC (Asp-His-His-Cys) proteins has emerged as protein palmitoyl acyltransferases (PATs). However, mechanisms that regulate these PATs in a physiological context remain unknown. In this study, we efficiently monitored the dynamic palmitate cycling on synaptic scaffold PSD-95. We found that blocking synaptic activity rapidly induces PSD-95 palmitoylation and mediates synaptic clustering of PSD-95 and associated AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors. A dendritically localized DHHC2 but not the Golgi-resident DHHC3 mediates this activity-sensitive palmitoylation. Upon activity blockade, DHHC2 translocates to the postsynaptic density to transduce this effect. These data demonstrate that individual DHHC members are differentially regulated and that dynamic recruitment of protein palmitoylation machinery enables compartmentalized regulation of protein trafficking in response to extracellular signals
Genome evolution in the allotetraploid frog Xenopus laevis
To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of ???fossil??? transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.ope