Enabling Machine-aided Cryptographic Design

The design of cryptographic primitives such as digital signatures and public-key encryption is very often a manual process conducted by expert cryptographers. This persists despite the fact that many new generic or semi-generic methods have been proposed to construct new primitives by transforming existing ones in interesting ways. However, manually applying transformations to existing primitives can be error-prone, ad-hoc and tedious. A natural question is whether automating the process of applying cryptographic transformations would yield competitive or better results? In this thesis, we explore a compiler-based approach for automatically performing certain cryptographic designs. Similar approaches have been applied to various types of cryptographic protocol design with compelling results. We extend this same approach and show that it also can be effective towards automatically applying cryptographic transformations. We first present our extensible architecture that automates a class of cryptographic transformations on primitives. We then propose several techniques that address the aforementioned question including the Charm cryptographic framework, which enables rapid prototyping of cryptographic primitives from abstract descriptions. We build on this work and show the extent to which transformations can be performed automatically given these descriptions. To illustrate this automation, we present a series of cryptographic tools that demonstrate the effectiveness of our automated approach. Our contributions are listed as follows: - AutoBatch: Batch verification is a transformation that improves signature verification time by efficiently processing many signatures at once. Historically, this manual process has been prone to error and tedious for practitioners. We describe the design of an automated tool that finds efficient batch verification algorithms from abstract descriptions of signature schemes. - AutoGroup: Cryptographers often prefer to describe their pairing-based constructions using symmetric group notation for simplicity, while they prefer asymmetric groups for implementation due to the efficiency gains. The symmetric- to-asymmetric translation is usually performed through manual analysis of a scheme and finding an efficient translation that suits applications can be quite challenging. We present an automated tool that uses SMT solvers to find efficient asymmetric translations from abstract descriptions of cryptographic schemes. - AutoStrong: Strongly unforgeable signatures are desired in practice for a variety of cryptographic protocols. Several transformations exist in the literature that show how to obtain strongly unforgeable signatures from existentially unforgeable ones. We focus on a particular highly-efficient transformation due to Boneh, Shen and Waters that is applicable if the signature satisfies a notion of partitioning. Checking for this property can be challenging and has been less explored in the literature. We present an automated tool that also utilizes SMT solvers to determine when this property is applicable for constructing efficient strongly unforgeable signatures from abstract descriptions. We anticipate that these proof-of-concept tools embody the notion that certain cryptographic transformations can be safely and effectively outsourced to machines

Use of Recycled Polypropylene Grains as Partial Replacement of Fine Aggregate in Reinforced Concrete Beams

Waste product from polyethylene materials are non-biodegradable and they form the bulk of the materials been used today. This paper looked into how this waste product was recycled in to polypropylene grains of sizes <4.5 mm and used to partially replace fine aggregate in concrete. Sieve analysis was carried out on the recycled polypropylene waste. Reinforced concrete beams (600 mm x 150 mm x 200 mm) and concrete cubes (150 mm x 150 mm x 150 mm) were made from the mixture of the recycled material at different percentages of 0%, 4%, 8%, 12% and 16%. The beams were subjected to bending moment test, while the cubes were subjected to compressive strength test. Results revealed that 43.71% of polypropylene grains passed through the 4.75 mm sieve. The compressive strength of the 4% mixture was 16.28 N/mm2 while the control was 19.07 N/mm2. The bending moment test showed that the control mix has the highest value of 14.70 kNm, while the 12% and 16% has the lowest value of 8.40 kNm each. Deflections in the polypropylene mixes were generally higher than the control. The work concluded that recycled polypropylene grains can be used as partially replacement of fine aggregate in concrete at below 4% replacement

The impact of rubber crumb on the mechanical and chemical properties of concrete

Various works have been carried out on both the physical and mechanical properties of rubberized concrete in previous research. But the chemical composition of rubberized concrete has not been fully investigated. The scanning electron microscopy (SEM) and energy-dispersive x-ray spectrum (EDX) analysis were used to determine the element composition and the peak intensity of chemical elements in the waste rubber concrete. The SEM and EDX analysis results showed that, ferrous iron, oxygen, calcium, and silicon were the dominant elements, and these elements reduced as more waste rubber were added to the concrete. Carbon and sulphur elements increased as rubber crumbs were added to the rubberized concrete. The work concluded that the presence of rubber crumb in the concrete samples contributed to both mechanical and chemical changes in the property of rubberized concrete

Production of lightweight concrete from waste tire rubber crumb

A lot of research has proposed the use of alternative materials in concrete, one of such material that has gained a lot of attention is the waste tire rubber. In this research, rubber crumb was used to partially replace fine aggregate in concrete at 0, 4, 8, 12, and 16% and represented as M0, M4, M8, M12, and M16, respectively. Sieve analysis was carried out on the rubber crumb and sand, while slump, compressive and tensile test were carried out on the concrete samples. The sieve analysis revealed that both the fine aggregate and rubber crumb are poorly graded. The slump test showed that the concrete losses it consistency as more rubber crumb was added. The 28 days compressive strength showed that there was a general reduction in strength. The work concluded that rubber crumb can be used to replace fine aggregate up to 16%, in lightweight concrete

Flexural Response of Reinforced Concrete Waffle Slab with Recycled Polyethylene Terephthalate (PET) in the Topping

The current trend of indiscriminate dumping of plastic wastes has lead researchers to look into the reuse of these materials especially in the building industry. In this work, waste plastic bottles polyethylene terephthalate (PET) were recycled to 4 mm diameter polymer rod and were used to replace wire mesh in the topping of waffle slab. The flexural strength and deformation of 12 waffle slabs with sizes of 700 mm × 700 mm × 120 mm, and 800 mm × 800 mm × 120 mm were determined with three samples for each size. The topping of six slabs were reinforced with the polymer rod while the remaining six were reinforced with wire mesh which served as the control. The laboratory test carried out showed that the young modulus of elasticity for polymer rod and wire mesh was 12,766 N/mm2 and 30,469 N/mm2 respectively. The average crack width for the waffle slabs reinforced with polymer rods and wire mesh range from 1 mm to 2.3 mm having maximum deflection of 42.93 mm and 40.64 mm respectively. The average ultimate flexural load was 50KN for both samples. The study concluded that the polymer rod could be used as topping in waffle slab

Assessment of the Hepatoprotective activity of the seeds of Hunteria umbellata (Hallier F.) on Carbon Tetrachloride (CCl4) Induced Liver Damage in Wistar Albino Rats

This study was designed to evaluate the hepatoprotective activity of the seeds of Hunteria umbellata (HU) on carbon tetrachloride (CCl4) induced rats. Rats of groups 1 (normal control), 3 and 5 were not treated with CCl4 while rats of groups 2 (negative control), 4 and 6 rats were treated with single dose of CCl4 (2 ml/kg) by intraperitoneal administration. Normal control group 1 rats were given distilled water, groups 3 and 4 rats were given 50 mg/kg of silymarin while groups 5 and 6 rats were given 500 mg/kg of HU. Treatment was administered orally for 28 days and sacrificed on the 29th day after an overnight fast. The weights of the rats were taken before and after the treatment. Blood samples were collected in heparinized tubes and biochemical analysis of liver functions and lipid profile tests were carried out on plasma. There was a significant change (p<0.05) in the levels of alanine aminotransferase, alkaline phosphatase, high density lipoprotein and triglycerides of the CCl4 induced group treated with HU compared to the CCl4 untreated group 2 animals. The results obtained showed that the ethanolic extract of HU has hepatoprotective property

The ChatGPT Artificial Intelligence Chatbot: How Well Does It Answer Accounting Assessment Questions?

ChatGPT, a language-learning model chatbot, has garnered considerable attention for its ability to respond to users’ questions. Using data from 14 countries and 186 institutions, we compare ChatGPT and student performance for 28,085 questions from accounting assessments and textbook test banks. As of January 2023, ChatGPT provides correct answers for 56.5 percent of questions and partially correct answers for an additional 9.4 percent of questions. When considering point values for questions, students significantly outperform ChatGPT with a 76.7 percent average on assessments compared to 47.5 percent for ChatGPT if no partial credit is awarded and 56.5 percent if partial credit is awarded. Still, ChatGPT performs better than the student average for 15.8 percent of assessments when we include partial credit. We provide evidence of how ChatGPT performs on different question types, accounting topics, class levels, open/closed assessments, and test bank questions. We also discuss implications for accounting education and research

COMBUSTION CHARACTERISTICS OF TORREFIED WOOD SAMPLES OF PINUS CARREBEA AND LEUCAENA LEUCOCEPHALA GROWN IN NIGERIA

Torrefaction of selected wood samples of Pinus Carrebea and Leucaena Leucocephala were carried out at temperatures ranging from 200 to 300°C to improve the energy parameters of biomass and to determine the effect of torrefication temperature on the physical and combustion properties of wood selected from Pinus carrebea and Leuceanea leucocephala grown in Nigeria. In this process the biomass hemicellulose is degraded, maintaining its cellulose and lignin content. The samples were dried and heated to 225, 250, 275, and 300°C. Then the torrefied mass was subjected to basic property testing on proximate analysis and heating value was calculated in order to understand the differences between raw material and its torrefied products. Specifically, the wood blocks changed from light brown to black, stemming from the partial carbonization at the wood surface. When the temperature is 225°C, the color of the wood is between dark brown and once the torrefaction temperatures are 250 and 275°C, the colors of the wood become dark and darker respectively. The results of the proximate analysis also showed that increasing of torrefied temperature; volatile fraction was reduced while fixed carbon was increased with increase in temperature from 21.34 to 52.74 and 18.58 to 56.83 for Leucaena leucocephala and Pinus carreabeanus respectively at 225 to 300°C. The volatile content is decreased from 78.58% to 62.76% with increase in temperature. Ash content of were within 1.57-3.41% of torrefied wood. It could be observed that the High calorific value (HCV for pine ranged between 19.80 and 28.06MJ/Kg for the top, 19.93and 24.96MJ/kg for middle with 19.72and 25.96MJ/Kg for base. The values recorded for raw sample and at 275°C been the lowest and highest respectively. The High calorific value (HCV) were found to be on the increase and nose dive at 300°C for the tree parts used in this research. The result revealed that for Leuceana the value increased from raw up to 275°C and at 300°C, a drop in the HHC was experienced. The result also showed that between raw and 250°C the value were statistically not at variance though higher value was recorded at 250°C (22.04MJ/kg). Likewise, between 275°C and 300°C there was no variance statistically, but higher value was observed for 275°C (26.32). It could be observed that the HHC for pine ranged between 19.80 and 28.06MJ/Kg for the top, 19.93 and 24.96MJ/kg for middle with 19.72 and 25.96MJ/Kg for base. The result also showed that between raw and 250 the value were statistically not at variance though higher value was recorded at 250 (22.04MJ/Kg). Likewise, between 275°C and 300°C there was no variance statistically, but higher value was observed for 275°C (26.32MJ/Kg). The proximate analyses revealed that the species are a suitable biomass source for torrefaction process and calorific value increase compared to control raw sample

Charm: A framework for rapidly prototyping cryptosystems

We describe Charm, an extensible framework designed for rapid prototyping of cryptographic systems that utilize the latest advances in cryptography, such as identity and attribute-based encryption, as well as the traditional cryptographic functions. Charm is designed to minimize code complexity, promote code re-use, and to automate interoperability, while not compromising on efficiency. Charm was designed from the ground up to support the implementation of advanced cryptographic schemes. It includes support for multiple cryptographic settings, an extensive library of re-usable code, and a protocol engine to aid in the development of interactive protocols. Our framework also provides a series of specialized tools that enable different cryptosystems to interoperate. We implemented over twenty cryptographic schemes using Charm, including some new ones that to our knowledge have never been built in practice. This paper describes our modular architecture, which includes a built-in benchmarking module that we use to compare the performance of primitives written in Python to comparable C implementations. We show that in many cases our techniques result in a potential order of magnitude decrease in code size, while inducing an acceptable performance impact