Papers by Raphael C . S . Machado
Discrete Applied Mathematics
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2019 II Workshop on Metrology for Industry 4.0 and IoT (MetroInd4.0&IoT)
Choosing and using a random number generator is no simple task. Most random number generators fai... more Choosing and using a random number generator is no simple task. Most random number generators fail statistical tests, revealing patterns in their output. Good generators can lead to disasters if not properly seeded. IoT products may not afford safe random number generators if these products are built on low resource hardware because safety tends to require more resources than not. Testing the chosen random number generator under the conditions of the product is important to know its limitations. We present an easy-to-use tool we have developed to bring the industry’s products the state-of-the-art in random number generator testing.
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2019 II Workshop on Metrology for Industry 4.0 and IoT (MetroInd4.0&IoT)
Networked Control Systems (NCS) are widely used in Industry 4.0 to obtain better management and o... more Networked Control Systems (NCS) are widely used in Industry 4.0 to obtain better management and operational capabilities, as well as to reduce costs. However, despite the benefits provided by NCSs, the integration of communication networks with physical plants can also expose these systems to cyber threats. This work proposes a link monitoring strategy to identify linear time-invariant transfer functions performed by a Man-in-the-Middle during controlled data injection attacks in NCSs. The results demonstrate that the proposed identification scheme provides adequate accuracy when estimating the attack function, and does not interfere in the plant behavior when the system is not under attack.
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2020 IEEE International Workshop on Metrology for Industry 4.0 & IoT, 2020
Public-Key Infrastructures are elementary building blocks to implement digital signatures (i.e., ... more Public-Key Infrastructures are elementary building blocks to implement digital signatures (i.e., digital notarization) and, hence, ensure information integrity, authenticity, and nonrepudiation. This feature is a promising alternative to improve the reliability of smart meters. However, conventional PKIs can be too expensive in scenarios that consist of a significant number of meters. In this work, we propose a blockchain-based PKI, describing how to tailor this solution to deal with specific aspects related to smart meter protection. We also implement our proposal as a smart contract with the Hyperledger Fabric platform. The results show our solution's feasibility and provide a reliable model to manage digital certificates for a wide diversity of smart devices.
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ACTA IMEKO, 2020
Statistical sampling and simulations produced by algorithms require fast random number generators... more Statistical sampling and simulations produced by algorithms require fast random number generators; however, true random number generators are often too slow for the purpose, so pseudorandom number generators are usually more suitable. But choosing and using a pseudorandom number generator is no simple task; most pseudorandom number generators fail statistical tests. Default pseudorandom number generators offered by programming languages usually do not offer sufficient statistical properties. Testing random number generators so as to choose one for a project is essential to know its limitations and decide whether the choice fits the project’s objectives. However, this study presents a reproducible experiment that demonstrates that, despite all the contributions it made when it was first published, the popular NIST SP 800-22 statistical test suite as implemented in the software package is inadequate for testing generators.
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2021 International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea), 2021
Understanding the importance of the maritime sector to the global economy and the peculiarities o... more Understanding the importance of the maritime sector to the global economy and the peculiarities of Ports, due to their critical role in an extremely dynamic environment, this paper looks to perform a systematic literature review, aiming to define the state of the art and to discover the processes and methodologies that may assist port facilities in conforming to IMO’s cyber security related resolutions. Meanwhile, seeking to further advances in research for this sector, this review also looks to acknowledge the current gaps in the field.
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2018 Workshop on Metrology for Industry 4.0 and IoT, 2018
The recent literature on nuclear science demonstrates the feasibility and the benefits of control... more The recent literature on nuclear science demonstrates the feasibility and the benefits of controlling large Pressurized Heavy Water Reactors (PHWR) through Networked Control Systems (NCS). However, the use of NCSs in PHWRs may also expose such critical systems to threats launched from the cyber domain. In the present paper, we propose a novel combination of two cyber-physical attacks (Passive System Identification attack and Covert Misappropriation attack) and evaluate their impact in a PHWR. The results indicate that, with this two attacks, the attacker is able to manipulate the power of the PHWR achieving, at the same time, a high degree of covertness. Moreover, the outcomes suggest the sensitivity and accuracy required for a monitoring system to detect this kind of attack, which may be considered in the development of standards and requirements for PHWR monitoring systems.
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Palavras-chave: Software Embarcado; Proteção; Rastreabilidade; Verificação de integridade 1. INTR... more Palavras-chave: Software Embarcado; Proteção; Rastreabilidade; Verificação de integridade 1. INTRODUÇÃO E OBJETIVOS Dispositivos com software embarcado estão cada vez mais sofisticados e presentes em diversas áreas, como por exemplo na infraestrutura avançada de medição. O problema da segurança destes dispositivos é um desafio pois normalmente estes estão expostos a operar muitas vezes em um ambiente hostil e de forma autônoma, sendo sujeitos a captura, engenharia reversa e manipulação. Neste contexto em que um atacante tem acesso físico ao dispositivo com poder de comprometê-lo, métodos tradicionais de segurança associados a princípios de segurança da informação (integridade, autenticidade e confidencialidade) não são suficientes, uma vez que estes métodos podem ser subvertidos caso o dispositivo seja manipulado, através da falsificação/adulteração da resposta de um resumo criptográfico ou de uma chave criptográfica. Garantir a integridade dos dispositivos utilizados, por exemplo, ...
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This work presents a methodology for fraud detection for accredited inspection bodies using Data ... more This work presents a methodology for fraud detection for accredited inspection bodies using Data Mining. This methodology is based on a non-supervised artificial neural network called Kohonen Networks. This technique allowed the extraction of patterns and the classification of fraudulent inspection bodies.
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Medidores inteligentes são medidores dotados de software embarcado e que possuem capacidade de co... more Medidores inteligentes são medidores dotados de software embarcado e que possuem capacidade de complexo processamento digital de dados. Medidores inteligentes já são uma realidade na maioria das áreas de Metrologia. Ao mesmo tempo em que trazem a possibilidade de uma série de novas aplicações, tais medidores inteligentes representam um novo desafio no que diz respeito à sua validação, em especial, no âmbito da Metrologia Legal. No presente trabalho, descrevemos as iniciativas do Inmetro em parceria com a Eletrobrás (Ceron) no sentido de produzir conhecimento e desenvolver ferramentas que sirvam de apoio às atividades de validação de medidores inteligentes de energia elétrica.
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Theoretical Computer Science, 2010
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Electronic Notes in Discrete Mathematics, 2010
We determine a surprising class for which edge-colouring is NP-complete but whose graphs are all ... more We determine a surprising class for which edge-colouring is NP-complete but whose graphs are all Type 1. The class of unichord-free graphs was recently studied by Trotignon and Vušković [N. Trotignon and K. Vušković. A structure theorem for graphs with no cycle with a unique chord and its consequences. To appear in J. Graph Theory. (Available online at http://www.comp.leeds.ac.uk/vuskovi/chord.ps.)] in
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Sensors
The growing demand for solutions related to measurement (e.g., digital sensors, smart meters, dis... more The growing demand for solutions related to measurement (e.g., digital sensors, smart meters, distributed measuring systems) imposes several concerns about information and process reliability. In this context, blockchain can play a crucial role as a platform to implement applications and activities in the context of legal metrology. In most countries, the National Metrology Institutes (NMIs) are responsible for promoting these initiatives. Thus, in this paper, we present a functional architecture to integrate NMIs in a collaborative blockchain network. We discuss the main aspects and features that an inter-NMI blockchain network must deliver. Furthermore, we implement our proposal using the Hyperledger Fabric platform. We connect peers from Physikalisch-Technische Bundesanstalt (PTB) (German NMI) and the National Institute of Metrology, Quality, and Technology (Inmetro) (Brazilian NMI) in a useful application that consists of a blockchain-based public-key infrastructure to identify ...
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Revista da Escola de Guerra Naval
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P2P E INOVAÇÃO
O Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro) utiliza, sistematicamente, a... more O Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro) utiliza, sistematicamente, a avaliação da conformidade em sua regulamentação. Na certificação de produtos, processos e serviços, há sete tipos de esquemas possíveis. No entanto, na inexistência de regras explícitas, observa-se, nos programas instituídos pelo Inmetro, a preferência pelo tipo 1b, ou certificação de lote, e pelo tipo 5, o mais completo dos esquemas, no que se refere às atividades de avaliação empregadas. A partir da revisão bibliográfica, este trabalho investigou como selecionar o esquema adequado na certificação. Foi elaborada uma sistemática de apoio à decisão, baseando-se nas variáveis relacionadas ao produto, processo produtivo, setor produtivo, mercado e canal de distribuição. A sistemática potencialmente promove a melhoria da qualidade regulatória do Inmetro e o aumento da transparência, além de constituir-se ferramenta útil para outros atores, do setor público ou privado, que sejam proprietário...
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Anais Estendidos do Simpósio Brasileiro de Sistemas de Informação (SBSI)
A detecção de socialbots em Redes Sociais Online tem sido objeto de diversos estudos baseados em ... more A detecção de socialbots em Redes Sociais Online tem sido objeto de diversos estudos baseados em aprendizado de máquina. Este trabalho apresenta o uso de um comitê de classificadores para melhorar a acurácia da identificação de socialbots. O comitê associa o conhecimento obtido por algoritmos de aprendizado de máquina ao conhecimento heurístico humano, obtido por entrevistas e formalizado por regras fuzzy. Os resultados mostram que estas abordagens são complementares, uma vez que o uso conjunto destes algoritmos em um comitê apresenta uma acurácia acima de 93%, maior do que os mesmos algoritmos utilizados isoladamente.
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Papers by Raphael C . S . Machado