A lightweight verifiable secret sharing scheme in IoTs

Verifiable secret sharing (VSS) is a fundamental tool of cryptography and distributed computing in Internet of things (IoTs). Since network bandwidth is a scarce resource, minimizing the number of verification data will improve the performance of VSS. Existing VSS schemes, however, face limitations in meeting the number of verification data and energy consumptions for low-end devices, which make their adoption challenging in resource-limited IoTs. To address above limitations, we propose a VSS scheme according to Nyberg’s oneway accumulator for one-way hash functions (NAHFs). The proposed scheme has two distinguished features: first, the security of the scheme is based on NAHFs whose computational requirements are the basic criteria for known IoT devices and, second, upon receiving only one verification data, participants can verify the correctness of both their shares and the secret without any communication. Experimental results demonstrate that, compared to the Feldman scheme and Rajabi-Eslami scheme, the energy consumption of a participant in the proposed scheme is respectively reduced by at least 24% and 83% for a secret

Secure and Efficient Implicit Certificates: Improving the Performance for Host Identity Protocol in IoT

Implicit certificates own the shorter public key validation data. This property makes them appealing in resource-constrained IoT systems where public key validation is performed very often, which is common in Host Identity Protocol (HIP). However, it is still a critical challenge in IoT how to guarantee the security and efficiency of implicit certificates. This article presents a forgery attack for the Privacy-aware HIP (P-HIP), and then propose a Secure and Efficient Implicit Certificate (SEIC) scheme that can improve the security of the P-HIP and the efficiency of elliptic-curve point multiplications for IoT devices. For a fix-point multiplication, the proposed approach is about 1:5 times faster than the method in SIMPL scheme. Furthermore, we improve the performance of SEIC with the butterfly key expansion process, and then construct an improved P-HIP. Experimental results show that the improved P-HIP can achieve the performance gains

Verifiably Distributed Multi-User Secret Sharing schemes

Distributed secret sharing techniques, where a specific secret is encoded into its shares which are conveyed to the IoT device or its user via storage nodes, are considered. A verifiably distributed secret sharing (VDSS) provides a way for a legitimate user to verify the secret he reconstructs through the downloaded shares while the secrecy condition is satisfied in a weak or a perfect sense. This article examines the impact of minimizing verification information in a VDSS on the communication complexity and storage overhead, and achieves the verifiability in resource-limited IoTs by aggregating the verification information of different devices/users. Then, two secure VDSS are proposed. The first VDSS attains the lower bound on the communication complexity while providing the fault tolerance. The second VDSS simultaneously achieves the lower bounds of both communication complexity and storage overhead while providing the balanced storage load, thus showing the scheme that is optimal in terms of both parameters

Regeneration of Alveolar Type I and II Cells from Scgb1a1-Expressing Cells following Severe Pulmonary Damage Induced by Bleomycin and Influenza

The lung comprises an extensive surface of epithelia constantly exposed to environmental insults. Maintaining the integrity of the alveolar epithelia is critical for lung function and gaseous exchange. However, following severe pulmonary damage, what progenitor cells give rise to alveolar type I and II cells during the regeneration of alveolar epithelia has not been fully determined. In this study, we have investigated this issue by using transgenic mice in which Scgb1a1-expressing cells and their progeny can be genetically labeled with EGFP. We show that following severe alveolar damage induced either by bleomycin or by infection with influenza virus, the majority of the newly generated alveolar type II cells in the damaged parenchyma were labeled with EGFP. A large proportion of EGFP-expressing type I cells were also observed among the type II cells. These findings strongly suggest that Scgb1a1-expressing cells, most likely Clara cells, are a major cell type that gives rise to alveolar type I and II cells during the regeneration of alveolar epithelia in response to severe pulmonary damage in mice..Singapore. National Research FoundationSingapore–MIT Alliance for Research and Technology (Infectious Disease-IRG research programme

A Cellular Pathway Involved in Clara Cell to Alveolar Type II Cell Differentiation after Severe Lung Injury

Regeneration of alveolar epithelia following severe pulmonary damage is critical for lung function. We and others have previously shown that Scgb1a1-expressing cells, most likely Clara cells, can give rise to newly generated alveolar type 2 cells (AT2s) in response to severe lung damage induced by either influenza virus infection or bleomycin treatment. In this study, we have investigated cellular pathway underlying the Clara cell to AT2 differentiation. We show that the initial intermediates are bronchiolar epithelial cells that exhibit Clara cell morphology and express Clara cell marker, Scgb1a1, as well as the AT2 cell marker, pro-surfactant protein C (pro-SPC). These cells, referred to as pro-SPC[superscript +] bronchiolar epithelial cells (or SBECs), gradually lose Scgb1a1 expression and give rise to pro-SPC[superscript +] cells in the ring structures in the damaged parenchyma, which appear to differentiate into AT2s via a process sharing some features with that observed during alveolar epithelial development in the embryonic lung. These findings suggest that SBECs are intermediates of Clara cell to AT2 differentiation during the repair of alveolar epithelia following severe pulmonary injury.Singapore-MIT Alliance for Research and Technology Center. Infectious Disease Research Grou

Drought Propagation Patterns under Naturalized Condition Using Daily Hydrometeorological Data

Drought propagation pattern forms a basis for establishing drought monitoring and early warning. Due to its regional disparity, it is necessary and significant to investigate the pattern of drought propagation in a specific region. With the objective of improving understanding of drought propagation pattern in the Luanhe River basin, we first simulated soil moisture and streamflow in naturalized situation on daily time scale by using the Soil and Water Assessment Tool (SWAT) model. The threshold level method was utilized in identifying drought events and drought characteristics. Compared with meteorological drought, the number of drought events was less and duration was longer for agricultural and hydrological droughts. The results showed that there were 3 types of drought propagation pattern: from meteorological drought to agricultural/hydrological drought (M-A/H), agricultural/hydrological drought without meteorological drought (NM-A/H), and meteorological drought only (M). To explain the drought propagation pattern, possible driven factors were determined, and the relations between agricultural/hydrological drought and the driven factors were built using multiple regression models with the coefficients of determination of 0.4 and 0.656, respectively. These results could provide valuable information for drought early warning and forecast

A Novel Mechanism Is Involved in Cationic Lipid-Mediated Functional siRNA Delivery

A key challenge for therapeutic application of RNA interference is to efficiently deliver synthetic small interfering RNAs (siRNAs) into target cells that will lead to the knockdown of the target transcript (functional siRNA delivery). To facilitate rational development of nonviral carriers, we have investigated by imaging, pharmacological and genetic approaches the mechanisms by which a cationic lipid carrier mediates siRNA delivery into mammalian cells. We show that ∼95% of siRNA lipoplexes enter the cells through endocytosis and persist in endolysosomes for a prolonged period of time. However, inhibition of clathrin-, caveolin-, or lipid-raft-mediated endocytosis or macropinocytosis fails to inhibit the knockdown of the target transcript. In contrast, depletion of cholesterol from the plasma membrane has little effect on the cellular uptake of siRNA lipoplexes, but it abolishes the target transcript knockdown. Furthermore, functional siRNA delivery occurs within a few hours and is gradually inhibited by lowering temperatures. These results demonstrate that although endocytosis is responsible for the majority of cellular uptake of siRNA lipoplexes, a minor pathway, probably mediated by fusion between siRNA lipoplexes and the plasma membrane, is responsible for the functional siRNA delivery. Our findings suggest possible directions for improving functional siRNA delivery by cationic lipids

Differentiation of Club Cells to Alveolar Epithelial Cells In Vitro

Club cells are known to function as regional progenitor cells to repair the bronchiolar epithelium in response to lung damage. By lineage tracing in mice, we have shown recently that club cells also give rise to alveolar type 2 cells (AT2s) and alveolar type 1 cells (AT1s) during the repair of the damaged alveolar epithelium. Here, we show that when highly purified, anatomically and phenotypically confirmed club cells are seeded in 3-dimensional culture either in bulk or individually, they proliferate and differentiate into both AT2- and AT1-like cells and form alveolar-like structures. This differentiation was further confirmed by transcriptomic analysis of freshly isolated club cells and their cultured progeny. Freshly isolated club cells express Sca-1 and integrin α6, markers commonly used to characterize lung stem/progenitor cells. Together, current study for the first time isolated highly purified club cells for in vitro study and demonstrated club cells’ capacity to differentiate into alveolar epithelial cells at the single-cell level.National Cancer Institute (U.S.) (P30-CA14051

Observation of EGFP-positive AT2s and AT1s in TMX-treated transgenic mice after bleomycin treatment.

<p><b>A–C.</b> Scgb1a1-CreER:ACTB-mT-EGFP transgenic mice were given tamoxifen and then treated with bleomycin. Shown are representative images of lung sections analyzed for EGFP (green), pro-SPC (red) and Scgb1a1 (blue) at 21 days post-treatment. Tomato red is not shown. Higher magnification of boxed area in (B) is shown as (C). Arrows in (C) indicate EGFP-positive AT1-like cells. <b>D–F.</b> Representative images of confocal analysis for EGFP (D), PDPN (E) and merged (F) of lung sectons from TMX-treated transgenic mice at 21 days post-bleomycin treatment. Arrows in (D–F) indicate EGFP and PDPN double-positive AT1s. Scale bars: (A, B) 1000 µm; (C–F) 20 µm.</p