Symmetrical Disguise: Realizing Homomorphic Encryption Services from Symmetric Primitives

Homomorphic Encryption (HE) is a modern cryptographic technique that allows direct computations on encrypted data. While relatively new to the mainstream debate, HE has been a solid topic in research for decades. However, and despite the technological advances of the past years, HE’s inefficiencies render it impractical for deployment in realistic scenarios. Hence research in the field is still in its initial phase. To overcome certain challenges and bring HE closer to a realization phase, researchers recently introduced the promising concept of Hybrid Homomorphic Encryption (HHE) – a primitive that combines symmetric cryptography with HE. Using HHE, users perform local data encryptions using a symmetric encryption scheme and then outsource them to the cloud. Upon reception, the cloud can transform the symmetrically encrypted data to homomorphic ciphertexts without decrypting them. Such an approach can be seen as an opportunity to build new, privacy-respecting cloud services, as the most expensive operations of HE can be moved to the cloud. In this work, we undertake the task of designing a secure cryptographic protocol based on HHE. In particular, we show how HHE can be used as the main building block of a protocol that allows an analyst to collect data from multiple sources and compute specific functions over them, in a privacy-preserving way. To the best of our knowledge, this is the first work that aims at demonstrating how HHE can be utilized in realistic scenarios, through the design of a secure protocol

Footsteps in the fog: Certificateless fog-based access control

The proliferating adoption of the Internet of Things (IoT) paradigm has fuelled the need for more efficient and resilient access control solutions that aim to prevent unauthorized resource access. The majority of existing works in this field follow either a centralized approach (i.e. cloud-based) or an architecture where the IoT devices are responsible for all decision-making functions. Furthermore, the resource-constrained nature of most IoT devices make securing the communication between these devices and the cloud using standard cryptographic solutions difficult. In this paper, we propose a distributed access control architecture where the core components are distributed between fog nodes and the cloud. To facilitate secure communication, our architecture utilizes a Certificateless Hybrid Signcryption scheme without pairing. We prove the effectiveness of our approach by providing a comparative analysis of its performance in comparison to the commonly used cloud-based centralized architectures. Our implementation uses Azure – an existing commercial platform, and Keycloak – an open-source platform, to demonstrate the real-world applicability. Additionally, we measure the performance of the adopted encryption scheme on two types of resource-constrained devices to further emphasize the applicability of the proposed architecture. Finally, the experimental results are coupled with a theoretical analysis that proves the security of our approach

Management of Diabetes and Hypertension among Tswana and Zulu Traditional Health Practitioners: A Comparative Cross-Sectional Study Using a Mixed-Methods Approach

Diabetes and hypertension contribute to a considerable burden of disease in sub-Saharan Africa (SSA), being largely due to poor diet habits, smoking and alcohol abuse. The study was aimed at providing evidence on the use of traditional medicine (TM) essential for managing these conditions by Zulu and Tswana traditional health practitioners (THPs). Data collection took place in the uMgungundlovu and uThukela Districts in KwaZulu-Natal (KZN) Province, and the Bojanala, Dr Ruth Sekgopomati Districts, in North-West Province, South Africa. Snowball sampling resulted in 863 THPs participating, 437 Zulus and 426 Tswanas face-to-face interviews were conducted using a semi-structured questionnaire to obtain qualitative and quantitative information about the objectives of the study. Most of Zulu and Tswana THPs acquired knowledge from a single source to manage diabetes and hypertension. The Zulu THPs acquired knowledge as a gift from birth while the Tswana’s acquired knowledge from family members. Management was solely based on traditional knowledge, with the two groups having a similar cultural understanding of the two conditions and their clinical features, which were comparable to Orthodox Conventional Medicine (OCM) signs and symptoms. Treatment modalities mainly consisted of ethnopharmacological preparations of herbal mixtures concoctions and decoctions. There were similarities in the Zulu and Tswana THPs cultural understanding of these two diseases, descriptions of clinical features of diabetes and hypertension, and ethnopharmacological preparations used in their management. The findings are intended as a guide to developing a treatment framework that enables a common understanding of traditional practices to manage the two conditions

MetaPriv: Acting in Favor of Privacy on Social Media Platforms

Social networks such as Facebook (Since October 2021 is also known as META) (FB) and Instagram are known for tracking user online behaviour for commercial gain. To this day, there is practically no other way of achieving privacy in said platforms other than renouncing their use. However, many users are reluctant in doing so because of convenience or social and professional reasons. In this work, we propose a means of balancing convenience and privacy on FB through obfuscation. We have created MetaPriv, a tool based on simulating user interaction with FB. MetaPriv allows users to add noise interactions to their account so as to lead FB’s profiling algorithms astray, and make them draw inaccurate profiles in relation to their interests and habits. To prove our tool’s effectiveness, we ran extensive experiments on a dummy account and two existing user accounts. Our results showed that, by using our tool, users can achieve a higher degree of privacy in just a couple of weeks. We believe that MetaPriv can be further developed to accommodate other social media platforms and help users regain their privacy, while maintaining a reasonable level of convenience. To support open science and reproducible research, our source code is publicly available online

Amounts of NPK removed from soil in harvested coffee berries as guiding baseline for planning fertilizer requirements of coffee in Ghana

Monthly samples of ripened improved robusta coffee berries from compact and large growth forms from three locations, which are representative of the main ecological zones where coffee is grown in Ghana, were taken for 3 years. The pulp and parchment and beans were analysed for N, P and K contents. The amounts of N, P and K removed from the soil in the harvested coffee berries were estimated from the concentrations of the nutrients in the pulp and parchment and beans, and the yield of coffee at each location. The mean NPK contents of the berries were 2.18, 0.08, 2.56 and 2.07, 0.08, 2.52 per cent for compact and large growth forms, respectively. The N and P concentrations in the pulp and parchment were lower than in the bean, while the K content was higher in the pulp and parchment than in the bean across the locations. The N, P and K concentrations of the coffee berries were not significantly different among the growth forms. Coffee berries from suitable and moderately suitable sites removed significantly (P<0.05) higher amounts of N and K than the berries from the marginally suitable site, while the P contents of the berries were significantly (P<0.05) lower than N and K across the locations. Regardless of the coffee growth forms, the demand for N and K may be higher than P. A fertilizer rate of 30 kg N, 1 kg P, and 33 kg K ha-1 may serve as a basis for planning fertilizer requirements of mature coffee in Ghana

Bio-recovery of N and P from an anaerobic digester effluent: The potential of duckweed (Lemna minor)

The possibility of growing duckweed (Lemna minor) on anaerobic digester effluent and its nitrogen and phosphorus acquisition potential was studied. Duckweed was cultured for 21 days on an anaerobic digester effluent using two methods: static aeration (SAT) and normal batch reactor (NBR) techniques, respectively. The treatments involved pure effluent and 1/10, 1/25 and 1/50 effluent dilutions, respectively. Fifty duckweed fronds were grown in the anaerobic digester effluent for 21 days. At the end of the growth period, phosphate levels, total ammonium nitrogen (TAN) andtotal oxidized nitrogen (TON) contents of the growth media were determined. Total nitrogen concentration and orthophosphate P content in the duckweed were also determined. The results obtained indicated that duckweed was capable of growing on the anaerobic digester effluent provided its TAN content did not exceed 42 mg N l-1. Nitrogenuptake by the duckweed from the effluent ranged between 53 and 115.7 mg l-1 whereas P uptake varied from 1.40 to 8.4 mg P l-1. The relative growth rate of duckweed in the anaerobic digester effluent was observed to be comparable to literature value of 0.22 mg day -1. The results have demonstrated that duckweed has the potential to recover N and P from anaerobic digester effluent

Urban sprawl and microclimate in the Ga East Municipality of Ghana

Climatic elements such as temperature and rainfall provide great and unquantifiable benefits to human health. However, rapid urban sprawl has the tendency to undermine these health consequences. The relationship between urban sprawl and microclimate in the Ga East Municipality has been assessed to present the extent of sprawl that inhibit temperature and rainfall in recent times. Methodologically, satellite imagery and meteorological data (minimum and maximum temperature and rainfall) from 1990 to 2020 were used. The results indicate that rapid urban sprawl in recent times has significantly undermined the local climate through land use and land cover changes. There was strong statistical relationships between temperature and built-up areas (p \u3c 0.05), grass/shrub cover (p \u3c 0.04) and all vegetation cover (p \u3c 0.03). There was also strong statistical relationship between rainfall and built-up areas (p \u3c 0.03), grass/shrub cover (p \u3c 0.04) and all vegetation (p \u3c 0.02). Thus, expansion in built up areas and reduced grass/shrub cover led to increases in temperature, rainfall and surface water run off while reduction in all vegetation led to increase in both temperature and rainfall. These changes in climate brought about by urban sprawl will affect crop production, increase cataclysmic floods as well as growth of some harmful insects. There is the need for the amalgamation of urban growth and climate change into spatial planning through an all-embracing approach

Efficacy of Corncob and Rice Husk Biochar as Liming Agent and Phosphorus Source for Growth of Soybean in Two Acid Soils

Soil acidity, unavailability and high cost of conventional liming materials are major constraints to soybean production in the Western Region of Ghana. Research has shown that biochar produced from agricultural waste has high concentration of basic cations and available P that could be exploited for use as liming material and/or P source. However, the biochar type that will provide an ideal soil pH and P availability for soybean production in acid soils has received little attention. Therefore, for this study, two acid soils namely; Ankasa Series (Typic Hapludox) and Tikobo Series (Typic Hapludult) were amended with corncob and rice husk biochar types charred at 500 and 700 oC at a rate of 80 tons/ha in a pot experiment in a screen house to ascertain the efficacy of the biochar types as agricultural lime and P sources for soybean growth. The Ca equivalent of the biochar types from CaCO3 was amended to the soils to serve as realistic control. The soils were arranged in a completely randomized design in a screen house to allow for pH equilibration. After pH equilibration, inoculated soybean seeds were sown at stake. Nitrogen was applied at rates of 0 kg/ha and 10 kg/ha. Phosphorus from TSP was applied at 0 and biochar P equivalent to the non-biochar-amended soils. Extra 30 kg P/ha from TSP was applied to some of the biochar amended soils to ascertain if any, the combined effect of synthetic and biochar P on soybean growth. At flower initiation, the crops were harvested, root volume and P uptake determined. Amended with rice husk biochar charred at 700 oC, the shoot P uptake was 1.3 times more in both the Typic Hapludox and the Typic Hapludult than the same soils amended with conventional lime with equivalent biochar P from the synthetic source

Convex Regularization Method for Solving Cauchy Problem of the Helmholtz Equation

In this paper, we introduce the Convex Regularization Method (CRM) for regularizing the (instability) solution of the Helmholtz equation with Cauchy data. The CRM makes it possible for the solution of Helmholtz equation to depend continuously on the small perturbations in the Cauchy data. In addition, the numerical computation of the reg- ularized Helmholtz equation with Cauchy data is stable, accurate and gives high rate of convergence of solution in Hilbert space. Undoubtedly, the error estimated analysis associated with CRM is minimal.Mathematics Subject Classi cation: 44B28; 44B30Keywords: Convex Regularization Method, ill-posed Helmholtz equation with Cauchy data, stable solutio