Integrating post-quantum cryptography (NTRU) in the TLS protocol

Dissertação de mestrado em Computer ScienceWe aim to integrate new “suites”, using post-quantum authentication and encryption tech niques, in the TLS protocol. Namely, this project is dedicated to integrating algorithms belonging to the NTRU family of cryptossystems in the OpenSSL library and in the Python package “Cryptography”. Even though all the algorithms included in this project have already been imple mented as part of their submissions to the NIST Post-Quantum Standartization project, currently there doesn’t seem to exist a way to perform prototyping and testing of these cryp tossystems in real-life use cases, and it would be interesting to create such tools. We also aim to test if these algorithms could be further optimized for speed and efficiency by comparing the reference implementations (submited to NIST and publicly avail able) with our own implementations that perform some required mathematical operations in a very efficient manner (by using specialized number theory libraries).Pretende-se integrar novas “suites” no protocolo TLS que usem técnicas de autenticação e cifra na categoria de técnicas pós-quanticas. Nomeadamente, este projecto é dedicado à integração de algoritmos da família NTRU na biblioteca OPENSSL e na “package” Cryptography para o Python. Apesar de todos os algoritmos contemplados neste projeto já terem sido implementa dos no âmbito da sua submissão ao NIST Post-Quantum Standartization project, actualmente não parece existir forma de testar e prototipar estes criptossistemas em casos de uso realistas, e seria interessante desenvolver ferramentas que o permitam. Pretende-se também aferir se estes algoritmos podem ser optimizados em eficiência e velocidade de execução, comparando as implementações de referência (submetidas ao NIST e disponiveis publicamente) com as nossas implementações, que efectuam algumas operações matemáticas necessárias de forma muito eficiente (com recusro a bibliotecas de teoria de números especializadas)

Using Machine Learning to Generate Test Oracles: A Systematic Literature Review

Machine learning may enable the automated generation of test oracles. We have characterized emerging research in this area through a systematic literature review examining oracle types, researcher goals, the ML techniques applied, how the generation process was assessed, and the open research challenges in this emerging field.Based on a sample of 22 relevant studies, we observed that ML algorithms generated test verdict, metamorphic relation, and - most commonly - expected output oracles. Almost all studies employ a supervised or semi-supervised approach, trained on labeled system executions or code metadata - including neural networks, support vector machines, adaptive boosting, and decision trees. Oracles are evaluated using the mutation score, correct classifications, accuracy, and ROC. Work-to-date show great promise, but there are significant open challenges regarding the requirements imposed on training data, the complexity of modeled functions, the ML algorithms employed - and how they are applied - the benchmarks used by researchers, and replicability of the studies. We hope that our findings will serve as a roadmap and inspiration for researchers in this field

Using Machine Learning to Generate Test Oracles: A Systematic Literature Review

Machine learning may enable the automated generation of test oracles. We have characterized emerging research in this area through a systematic literature review examining oracle types, researcher goals, the ML techniques applied, how the generation process was assessed, and the open research challenges in this emerging field. Based on a sample of 22 relevant studies, we observed that ML algorithms generated test verdict, metamorphic relation, and - most commonly - expected output oracles. Almost all studies employ a supervised or semi-supervised approach, trained on labeled system executions or code metadata - including neural networks, support vector machines, adaptive boosting, and decision trees. Oracles are evaluated using the mutation score, correct classifications, accuracy, and ROC. Work-to-date show great promise, but there are significant open challenges regarding the requirements imposed on training data, the complexity of modeled functions, the ML algorithms employed - and how they are applied - the benchmarks used by researchers, and replicability of the studies. We hope that our findings will serve as a roadmap and inspiration for researchers in this field.Comment: Pre-print. Article accepted to 1st International Workshop on Test Oracles at ESEC/FSE 202

The Integration of Machine Learning into Automated Test Generation: A Systematic Mapping Study

Context: Machine learning (ML) may enable effective automated test generation. Objective: We characterize emerging research, examining testing practices, researcher goals, ML techniques applied, evaluation, and challenges. Methods: We perform a systematic mapping on a sample of 102 publications. Results: ML generates input for system, GUI, unit, performance, and combinatorial testing or improves the performance of existing generation methods. ML is also used to generate test verdicts, property-based, and expected output oracles. Supervised learning - often based on neural networks - and reinforcement learning - often based on Q-learning - are common, and some publications also employ unsupervised or semi-supervised learning. (Semi-/Un-)Supervised approaches are evaluated using both traditional testing metrics and ML-related metrics (e.g., accuracy), while reinforcement learning is often evaluated using testing metrics tied to the reward function. Conclusion: Work-to-date shows great promise, but there are open challenges regarding training data, retraining, scalability, evaluation complexity, ML algorithms employed - and how they are applied - benchmarks, and replicability. Our findings can serve as a roadmap and inspiration for researchers in this field.Comment: Under submission to Software Testing, Verification, and Reliability journal. (arXiv admin note: text overlap with arXiv:2107.00906 - This is an earlier study that this study extends

Avaliação multicritério do potencial de produção de bioetanol através de resíduos florestais e agrícolas

Trabalho Final de Mestrado para a obtenção do grau de Mestre em Engenharia Química e BiológicaVivemos em contagem decrescente. Com o fim à vista das reservas de petróleo, todos os recursos que nos chegam através do seu processamento e que suportam, confortam e regulam o nosso dia-a-dia prontamente terão o seu término. Encontrar e consolidar fontes alternativas de energia, de preferência limpas, renováveis e, sobretudo, sustentáveis, para a sobrevivência do Homem nunca foi tão necessário. A adoção de políticas de economia circular que possibilitem recuperar, transformar e reaproveitar produtos à partida sem utilidade, destino e valor algum, para a produção de recursos que façam funcionar todo um sistema económico minimiza o impacte ambiental resultante do descarte desses resíduos, permite criar postos de trabalho e diminui os custos decorrentes da produção. Neste contexto, os biocombustíveis de segunda geração assumem um papel principal na mudança do rumo da Indústria e da Sociedade. O Bioetanol encontra-se neste caminho, que é imperioso percorrer. Partindo de uma revisão bibliográfica referente aos últimos anos em que se relata os diversos tipos de tecnologias passíveis de serem utilizadas num processo de produção de Bioetanol de segunda geração e se analisam seus respetivos pontos fortes e fracos, apresenta-se um estudo que, além de abordar a situação do país face a esta temática, permitiu eleger o melhor processo de produção de Bioetanol 2G a implementar em Portugal, a partir essencialmente de residuos florestais e agrícolas existentes em território nacional. Para o efeito, construíram-se dois modelos multicritério de avaliação e de apoio à decisão, recorrendo ao software M-MACBETH. Enquanto o 1º modelo permitiu determinar os resíduos com maior potencial para a produção de Bioetanol, o 2º modelo possibilitou selecionar a melhor tecnologia de produção deste biocombustível, que utiliza como matéria-prima os resíduos selecionados no 1º modelo. Com efeito, no 1º modelo, a avaliação multicritério conduziu à seleção dos resíduos de eucalipto, de Paulownia Tomentosa, de tabaco, de castanha, de milho, de trigo e de cevada, como os mais promissores para a produção de Bioetanol e, no 2º modelo, a avaliação multicritério efetuada conduziu ao processo de produção mais atrativo do ponto de vista tecnológico, que é aquele que, partindo de resíduos de eucalipto, recorre a um pré-tratamento Organossolv de etanol/água, seguido de uma hidrólise enzimática e de uma fermentação alcoólica efetuadas em simultâneo. Efetuou-se ainda uma análise custo-benefício, suportada numa breve estimativa dos custos de produção dos diversos processos tecnológicos em estudo, tendo elegido, como mais promissoras, não só a opção acima referida de resíduos de eucalipto, mas também a opção que, utilizando resíduos de Paulownia Tomentosa como matéria-prima, é capaz de produzir Bioetanol a partir de um pré-tratamento de Autohidrólise com dois estágios, seguido de uma hidrólise enzimática e de uma fermentação alcoólica efetuadas separadamente. Para além destas opções, também poderá ser promissora a utilização de resíduos de castanha num pré-tratamento de hidróxido de sódio, seguido de uma hidrólise enzimática e de uma fermentação alcoólica efetuadas em simultâneo, se bem que com um muito menor benefício, mas também com um custo inferior. Concluiu-se que os residuos florestais e agrícolas apresentam potencial relevante para motivar uma aposta na sua recolha e tratamento à escala industrial e para implementação de um modelo de negócio.We live in countdown. With the end in sight of the oil reserves, all the resources that arrive to us through their processing and that support, comfort and regulate our daily lives will promptly end. Finding and consolidating alternative energy sources, preferably clean, renewable and, above all, sustainable, for the survival of Man has never been more necessary. The adoption of circular economy policies that make it possible to recover, transform and reuse products without any use, destination, or value at the outset, for the production of resources that make an entire economic system work, minimizes the environmental impact resulting from the disposal of this waste, allows the creation of stations of labor and lowers production costs. In this context the second-generation biofuels assume a main role in changing the course of Industry and Society. Bioethanol is on this path, which is imperative. Based on a literature review referring to the last few years in which the various types of technologies that can be used in a second generation Bioethanol production process are reported and their respective strengths and weaknesses are analyzed, a study is presented that, in addition to addressing the country's situation in relation to this issue, allowed for the choice of the best 2G Bioethanol production process to be implemented in Portugal, based essentially on forestry and agricultural waste existing in the national territory. For this purpose, two multicriteria evaluation and decision support models were built, using the M-MACBETH software. While the 1st model made it possible to determine the residues with the greatest potential for the production of Bioethanol, the 2nd model made it possible to select the best production technology for this biofuel, which uses the residues selected in the 1st model as raw material. Indeed, in the 1st model, the multi-criteria evaluation led to the selection of eucalyptus, Paulownia Tomentosa, tobacco, chestnut, corn, wheat and barley residues as the most promising for the production of Bioethanol, and in the 2nd In this model, the multi-criteria evaluation carried out led to the most attractive production process from a technological point of view, which is the one that, starting from eucalyptus residues, uses an Organossolv pre-treatment of ethanol/water, followed by an enzymatic hydrolysis and an alcoholic fermentation carried out simultaneously. A cost-benefit analysis was also carried out, supported by a brief estimate of the production costs of the various technological processes under study, having chosen, as the most promising, not only the aforementioned option of eucalyptus residues, but also the option that, using Paulownia Tomentosa residues as raw material, is capable of producing Bioethanol from a two-stage Autohydrolysis pre-treatment, followed by an enzymatic hydrolysis and an alcoholic fermentation carried out separately. In addition to these options, the use of chestnut residues in a pre-treatment of sodium hydroxide may also be promising, followed by an enzymatic hydrolysis and an alcoholic fermentation carried out simultaneously, although with much less benefit, but also with a lower cost. It was concluded that forestry and agricultural waste has a relevant potential to encourage a commitment to its collection and treatment on an industrial scale and to implement a business model.info:eu-repo/semantics/publishedVersio

Variabilidad temporal del crecimiento, talla y duración larvaria, y reclutamiento de un lábrido, Coris julis (Pisces: Labridae), de las Azores

Temporal variability in the size at settlement (SAS), age at settlement (PLD), larval growth and recruitment patterns of a temperate wrasse, Coris julis, were examined over two recruitment seasons for a single island site from the Azores archipelago in the northeastern Atlantic. Relationships between these early life-history traits and recruitment variability over time were also investigated. Average PLD and SAS varied significantly among sampling dates over the settlement season, increasing consistently over time. This pattern was persistent over two consecutive summers. Larval growth was not a good predictor for PLD or SAS, which were in turn positively correlated with each other. Differences in recruitment magnitude over time were not related to SAS, PLD or larval growth. Instead, we found that recruits whose early pelagic stage (first 30 d) overlapped part of a period of enhanced growth (above average and independent of larval age), tended to result in the largest recruitment events; these tended to occur in the mid season. Larvae from earlier and later settlement events, overlapping periods of depressed growth, were linked to more modest recruitment events. We hypothesize that short PLD, with resulting small SAS is favoured early in the season, when post-settlement density is lowest. Over the course of the settlement season, as recruits accumulate competition may increase, and larger SAS (associated with longer PLD), may provide a competitive/survival advantage.La variabilidad temporal en la talla de reclutamiento (SAS), edad de reclutamiento (PLD), crecimiento larvario y patrón de reclutamiento en un lábrido de aguas templadas, Coris julis, fueron examinados en dos épocas de reclutamiento consecutivas, en una isla de las Azores (Atlántico nordeste). Se examinaron también las relaciones entre estas características y la variabilidad de reclutamiento temporal. La PLD y la SAS medios aumentaron significativamente a lo largo del período de reclutamiento en los dos veranos consecutivos. La PLD y la SAS se correlacionaron positivamente, pero el crecimiento larvario no fue un buen predictor de estas características. Las diferencias en magnitud de reclutamiento entre fechas de muestreo sucesivas no fueron explicadas por las SAS/PLD medias, ni tampoco por el crecimiento larvario. En cambio, encontramos que los reclutas cuyos primeros estadios de desarrollo pelágico (30 días) se solapaban, en parte, con un periodo de crecimiento intenso (por encima del promedio e independiente de de edad) resultaron en los mayores reclutamientos; que tienden a suceder a mitad de la estación. Las larvas de asentamientos tempranos o tardíos (periodos de solapamiento, con crecimiento disminuido), se asociaron a reclutamientos modestos. Se plantea la hipótesis de que las PLD cortas, con las resultantes pequeñas SAS deberían ser favorecidas en la fase más temprana del período de reclutamiento, cuando la densidad de juveniles es menor. A lo largo del período de asentamiento, a medida que los reclutas se acumulan, la competición puede aumentar, y las mayores SAS (asociadas a mayores PLD), pueden proporcionar una ventaja competitiva o de supervivencia

Reproducción y hábitat de desove del jurel dentón, Pseudocaranx dentex, en las Azores, Atlántico norte central

Reproductive biology and habitat preferences of the white trevally, Pseudocaranx dentex (Carangidae), were studied in the Azores islands, central north Atlantic, to determine the spatial and seasonal dynamics of habitat use of immature and mature fish. The sex ratio was close to 1:1 and fish matured at about 30 cm fork length. There were no differences in the maturation or length-weight relationships between sexes. The spawning season lasts from June to September. Underwater visual censuses showed that schools of mature individuals preferentially aggregate around the summits of offshore reefs during the spawning season. In contrast, schools of smaller, immature fish use inshore habitats all year round. Our data support the hypothesis that offshore reefs are a preferential spawning habitat of larger white trevally, and most possibly for a number of visitor pelagic predators as well. Inverse relationships between exploitation levels, abundance and size composition at the two different islands suggest that the summer fishery targeting trevally schools around offshore reefs has negatively impacted the population. These findings bring additional ecological and management relevance to offshore reefs.Se realizó un estudio de la biología reproductiva y las preferencias de hábitat del jurel dentón, Pseudocaranx dentex (Carangidae),en las islas Azores, Atlántico norte central, con el objetivo de comprender la dinámica espacial y estacional de individuos inmaduros y maduros en el uso del hábitat. Se observó un sex ratio próximo a 1:1 y una talla de primera madurez de 30 cm longitud de furca, sin diferencias entre sexos respecto a la talla de madurez, ni tampoco en la relación talla-peso. La época de reproducción se prolongó de junio a septiembre. Los muestreos visuales revelaron que durante la época de reproducción los individuos maduros se agregan preferentemente en torno de las coronas de arrecifes en mar abierto, mientras que los cardúmes de individuos inmaduros utilizan los hábitats costeros durante todo el año. Nuestros datos apoyan la hipótesis de que los arrecifes en mar abierto constituyen el hábitat preferente para el desove del jurel dentón y, muy probablemente, de otros predadores pelágicos. Una relación inversa entre los niveles de explotación y la abundancia y talla del jurel dentón en dos islas distintas sugiere que la pesquería de verano del jurel dentón ha afectado negativamente la población. Estos resultados ponen de manifiesto la relevancia, tanto ecológica como para la gestión, de los arrecifes en mar abierto

The multi-annual residency of juvenile smooth hammerhead shark in an oceanic island nursery

The increased risk of local extinction becomes critical for sharks depending on the narrow and isolated coastal habitats of oceanic islands. This includes large pelagic oceanic sharks that use such habitats as nurseries, as previously hypothesized for the smooth hammerhead Sphyrna zygaena, the least known of cosmopolitan large hammerhead sharks. We used a combination of acoustic and satellite telemetry in a juvenile population of Faial and Pico islands, Azores, mid-north Atlantic, to confirm if this isolated archipelago holds nurseries, and to answer questions related to their function and spatial-temporal stability. Our long-term acoustic tracking data showed a cluster of individual core home ranges in specific areas of north shore Faial, and surface positions from five Argos-linked tagged individuals also showed a clustering overlap in those areas for up to 1 year. These patterns seem to reveal a true habitat preference within the Faial-Pico island (sub) population of juvenile smooth hammerhead shark, and thus constitute strong evidence for this area to be considered a nursery. Some individuals remained in this nursery for up to 4 years, especially during summers. Sharks also showed a strong diel behavior, typically using the inshore nurseries during the day and moving further offshore during the night, during which they increased activity and dove deeper, most possibly to feed. We speculate that a combination of increased feeding opportunities, expanded trophic niche, and reduced predatory pressure may be a key evolutionary driver for the existence, prolonged use, and even preference of coastal nurseries at oceanic islands by juvenile smooth hammerhead shark. Given that these nurseries may constitute essential fish habitat for this species, they should be explicitly included in spatial management measures at the local and regional scales, as they may also play a role of greater importance to the north Atlantic population of this oceanic species.info:eu-repo/semantics/publishedVersio

Efficient and Effective Generation of Test Cases for Pedestrian Detection - Search-based Software Testing of Baidu Apollo in SVL

With the growing capabilities of autonomous vehicles, there is a higher demand for sophisticated and pragmatic quality assurance approaches for machine learning-enabled systems in the automotive AI context. The use of simulation-based prototyping platforms provides the possibility for early-stage testing, enabling inexpensive testing and the ability to capture critical corner-case test scenarios. Simulation-based testing properly complements conventional on-road testing. However, due to the large space of test input parameters in these systems, the efficient generation of effective test scenarios leading to the unveiling of failures is a challenge. This paper presents a study on testing pedestrian detection and emergency braking system of the Baidu Apollo autonomous driving platform within the SVL simulator. We propose an evolutionary automated test generation technique that generates failure-revealing scenarios for Apollo in the SVL environment. Our approach models the input space using a generic and flexible data structure and benefits a multi-criteria safety-based heuristic for the objective function targeted for optimization. This paper presents the results of our proposed test generation technique in the 2021 IEEE Autonomous Driving AI Test Challenge. In order to demonstrate the efficiency and effectiveness of our approach, we also report the results from a baseline random generation technique. Our evaluation shows that the proposed evolutionary test case generator is more effective at generating failure-revealing test cases and provides higher diversity between the generated failures than the random baseline