87 research outputs found
CryptoMask : Privacy-preserving Face Recognition
Face recognition is a widely-used technique for identification or
verification, where a verifier checks whether a face image matches anyone
stored in a database. However, in scenarios where the database is held by a
third party, such as a cloud server, both parties are concerned about data
privacy. To address this concern, we propose CryptoMask, a privacy-preserving
face recognition system that employs homomorphic encryption (HE) and secure
multi-party computation (MPC). We design a new encoding strategy that leverages
HE properties to reduce communication costs and enable efficient similarity
checks between face images, without expensive homomorphic rotation.
Additionally, CryptoMask leaks less information than existing state-of-the-art
approaches. CryptoMask only reveals whether there is an image matching the
query or not, whereas existing approaches additionally leak sensitive
intermediate distance information. We conduct extensive experiments that
demonstrate CryptoMask's superior performance in terms of computation and
communication. For a database with 100 million 512-dimensional face vectors,
CryptoMask offers and speed-ups
in terms of computation and communication, respectively.Comment: 18 pages,3 figures, accepted by ICICS202
Secret-Shared Shuffle with Malicious Security
A secret-shared shuffle (SSS) protocol permutes a secret-shared vector using a random secret permutation. It has found numerous applications, however, it is also an expensive operation and often a performance bottleneck. Chase et al. (Asiacrypt\u2720) recently proposed a highly efficient semi-honest two-party SSS protocol known as the CGP protocol. It utilizes purposely designed pseudorandom correlations that facilitate a communication-efficient online shuffle phase. That said, semi-honest security is insufficient in many real-world application scenarios since shuffle is usually used for highly sensitive applications. Considering this, recent works (CANS\u2721, NDSS\u2722) attempted to enhance the CGP protocol with malicious security over authenticated secret sharings. However, we find that these attempts are flawed, and malicious adversaries can still learn private information via malicious deviations. This is demonstrated with concrete attacks proposed in this paper. Then the question is how to fill the gap and design a maliciously secure CGP shuffle protocol. We answer this question by introducing a set of lightweight correlation checks and a leakage reduction mechanism. Then we apply our techniques with authenticated secret sharings to achieve malicious security. Notably, our protocol, while increasing security, is also efficient. In the two-party setting, experiment results show that our maliciously secure protocol introduces an acceptable overhead compared to its semi-honest version and is more efficient than the state-of-the-art maliciously secure SSS protocol from the MP-SPDZ library
Superconductivity in a new layered cobalt oxychalcogenide NaCoSeO with a 3 triangular lattice
Unconventional superconductivity in bulk materials under ambient pressure is
extremely rare among the 3 transition-metal compounds outside the layered
cuprates and iron-based family. It is predominantly linked to highly
anisotropic electronic properties and quasi-two-dimensional (2D) Fermi
surfaces. To date, the only known example of the Co-based exotic superconductor
was the hydrated layered cobaltate, NaCoO yHO, and its
superconductivity is realized in the vicinity of a spin-1/2 Mott state.
However, the nature of the superconductivity in these materials is still an
active subject of debate, and therefore, finding new class of superconductors
will help unravel the mysteries of their unconventional superconductivity. Here
we report the discovery of unconventional superconductivity at 6.3 K in
our newly synthesized layered compound NaCoSeO, in
which the edge-shared CoSe octahedra form [CoSe] layers with a
perfect triangular lattice of Co ions. It is the first 3 transition-metal
oxychalcogenide superconductor with distinct structural and chemical
characteristics. Despite its relatively low , material exhibits
extremely high superconducting upper critical fields, , which
far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles
calculations show that NaCoSeO is a rare example of
negative charge transfer superconductor. This new cobalt oxychalcogenide with a
geometrical frustration among Co spins, shows great potential as a highly
appealing candidate for the realization of high- and/or unconventional
superconductivity beyond the well-established Cu- and Fe-based superconductor
families, and opened a new field in physics and chemistry of low-dimensional
superconductors
Correlation between magnetic domain structures and quantum anomalous Hall effect in epitaxial MnBi2Te4 thin films
We use magnetic force microscopy (MFM) to study spatial uniformity of
magnetization of epitaxially grown MnBi2Te4 thin films. Compared to films which
exhibit no quantum anomalous Hall effect (QAH), films with QAH are observed to
have more spatial uniformity of magnetization with larger domain size. The
domain evolution upon magnetic field sweeping indicates that the magnetic
domains or the spatial nonuniformity of magnetization originates from the
strong pinning of the inherent sample inhomogeneity. A direct correlation
between the Hall resistivity and the domain size has been established by
analyzing a series of thin films with and without QAH. Our observation shows
that one has to suppress the spatial nonuniformity of magnetization to allow
the Hall resistivity to be quantized. The fact that a sizable longitudinal
resistivity remains even for the QAH sample suggests a quantized Hall insulator
scenario. Our work provides important insights to the understanding of the
quantization mechanism and the dissipation of the QAH state in MnBi2Te4 system.Comment: 14 pages, 4 figure
Stable structure and effects of the substrate Ti pre-treatment on the epitaxial growth of SrTiO
The structural and electronic properties of Ti in the SrTiO3/GaAs(001) interface are studied using the density functional theory. In all the structures examined, the formation energy of Ti on GaAs(001) decreases with decreasing Ti coverage. Sr or Ti adsorption atoms at the fourfold hollow sites with monolayer coverage on the GaAs(001) surface are the most energetically favorable. And, Sr atoms are adsorbed on the surface and Ti atoms are adsorbed below the surface, which is in agreement with the results in experiments. Ga vacancy can form spontaneously for the Ga-terminated (001) GaAs surface. Ti atoms may substitute Ga atoms, or accumulate at the voids inside the GaAs film during growth. Not only heterostructures with a regular perovskite but also heterostructures with Ti-insertion and Ti-substitution defects are investigated. The growth of the SrO-layer on the Ga-terminated surface is more stable, although all kinds of sequence among the SrO-,
TiO2-layer on a Ga-, As-terminated surface are possible. Substituting Ti for Ga enhances the stability of SrTiO3 on Ga-terminated (001) GaAs. The electronic structures and properties of the heterointerfaces SrTiO3/GaAs(001) are presented, and a metallic behavior is predicted at the interface of SrTiO3/GaAs with/without Ti-insertion
First-principles study of Sr adsorption on InN (0001)
Structures of Sr adsorbed on InN (0001) surfaces are theoretically investigated by first-principles calculations. The adsorption energies of Sr on InN (0001) decrease with decreasing Sr coverage. An InN (0001)-(2×2) surface structure covered by a 1/4 monolayer of Sr at the T4 sites may be the most energetically favourable. Sr atoms may substitute indium atoms, or accumulate at the voids inside InN films. The interstitial Sr defects may act as a potential source of compensation for the p-type behaviour of Sr-doped InN at the surface
Blood cells and hematological parameters of the mountain dragon, Diploderma micangshanensis (Squamata: Lacertilia: Agamidae)
Hematological characteristics reflect the health status of animals and their physiological adaptation to the environment. However, few studies focused on the species of Diploderma. In this study, the blood cells and the hematological parameters of Diploderma micangshanensis, a species endemic to China, were examined based on 48 healthy adult (32 males and 16 females). The blood cells and hematological parameters of D. micangshanensis were similar to those of other lizard species. Although the values of erythrocyte morphometric characters and hematological parameters varied between males and females, the differences were only significant in the case of the hematocrit and erythrocyte size, which may allow for higher oxygen availability in males. Hemoglobin, mean corpuscular hemoglobin concentration, and mean corpuscle volume were strongly affected by the snout-vent length and/or body mass, which reflect the physiological adaptation to the oxygen requirement of different individuals. This is the first report of hematological data from a species of Diploderma, and the results will provide data for research on the adaptive evolution and health assessment in this species and other congeners
Precise exploration technology of room pillar goaf in Shenfu Mining Area
In order to solve the problem of insufficient precision and ability of conventional exploration technology on the boundary of room pillar goaf, specific mining parameters, roof and surrounding rock stability and other factors, in this paper, the formation and occurrence characteristics of room and pillar goaf in Shenfu Mining Area are investigated in detail, and then the distribution range of room and pillar goaf is delineated by using ground geophysical fine imaging technology, and the target area is provided by the first borehole to guide drilling to quickly expose the goaf. Through high-precision hole peeping and 3D laser scanning technology, the accurate exploration of room pillar goaf in coal mine can be realized by continuous tracking. The advantage of this method is that it integrates the respective advantages of ground and borehole exploration technology through the surface geophysical fine imaging technology to guide drilling to quickly expose the room and pillar goaf, and the high-precision borehole scanning technology is used to realize the high-precision exploration of the room and pillar goaf boundary, specific mining parameters, roof and surrounding rock stability, and water accumulation conditions. At the same time, the drilling layout basis is sufficient, there is no invalid workload, saving the drilling quantity and drilling cost
Airborne Position and Orientation System for Aerial Remote Sensing
The airborne Position Orientation System (POS) can accurately measure space-time reference information and plays a vital role in aerial remote sensing system. It may be applied in a direct georeference system for optical camera and a motion imaging system for Synthetic Aperture Radar (SAR), which further advances efficiency and quality of imaging sensors. In this paper, the operation principle and components of airborne POS are introduced. Some key technologies of airborne POS are summarized. They include the error calibration and compensation, initial alignment, lever arm error modeling, time synchronization, and integrated estimation method. A high precision airborne POS has been developed and applied to a variety of aerial remote sensing systems
Mitochondrial genome of Diploderma micangshanense and its implications for phylogeny of the genus Diploderma
The lizard Diploderma micangshanense, which belongs to the family Agamidae is endemic to China. Here, we determined the complete mitogenome of D. micangshanense using an Illumina Hiseq X Ten sequencer. This mitogenome’s structure is a typical circular molecule of 16,467 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region. The overall base composition of D. micangshanensis is 34.1% A, 23.64% T, 13.62% C, and 28.64% G with a slight AT bias of 57.74%. Most mitochondrial genes except ND6 and seven tRNAs were encoded on the heavy strand. Notably, the trnP gene was encoded on the heavy strand instead of its typical light strand position, providing an example of gene inversion in vertebrate mitogenomes. Phylogenetic analysis indicated that D. micangshanensis had a close relationship with D. zhaoermii
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