El presente trabajo de investigación se centró en el Programa Nacional de Alimentación Escolar (PNAEQW), el cual ha enfrentado diversas situaciones críticas, entre los años de 2013 al 2018, presentándose el mayor número de casos de intoxicaciones en Lima en el 2018, representando el 43,60% del total nacional. Para ello, se planteó como objetivo general proponer un sistema de trazabilidad de la cadena de suministro, para mejorar la inocuidad alimentaria del PNAEQW. En tal sentido, se realizó el análisis y priorización de las causas del problema empleando los diagramas de Ishikawa y Pareto. Con la finalidad de evaluar los sistemas de trazabilidad, se utilizó el método de factores ponderados, seleccionando la tecnología blockchain junto con la plataforma Hyperledger y códigos QR, como los más adecuados; asimismo, se realizó un análisis de riesgos de la propuesta, empleando la guía PMBOK, estimando una contribución a la mejora de la inocuidad alimentaria mediante 3 escenarios: ideal, mediano, y pesimista, donde anteriormente se tenía que la cantidad de IIEE que han incumplido era del 32,70%, y bajo los 3 escenarios se obtuvo una mejora del 8,76%, 19,25%, y 24,90% respectivamente; y una mejora en la cantidad de niños intoxicados que pasó de 620 a 0. Finalmente, se estimó una inversión de S/ 11 250 863 soles con un VAN de S/ 25 434 596 y un beneficio costo de S/ 2,66, concluyendo que la propuesta se ajusta al presupuesto asignado por el gobierno, y se beneficiarán a 134 999 niños del departamento de Lambayeque.

Vehicular Ad-hoc Networks (VANETs) provide networks for smart vehicles and will enable future systems to provide services that enhance the overall transportation experience. However, these applications require consideration to possible damage to both property and human life. Communication between vehicles requires data immutability and user privacies to provide safe operation of the system. Blockchains can provide these properties and more to create a more secure and decentralized system. However, a chain’s security comes from the chain length. VANETs’ ephemeral connections provide harm limits how much data can be exchanged during vehicle rendezvous. This thesis investigates lightweight blockchains that operate with lower overheads. A survey of current techniques to accomplish this are discussed in Chapter 1. Two techniques are demonstrated within two separate environments to demonstrate the network overhead reductions when using a lightweight blockchain with respect to network and storage loads within these VANET environments.

Submitted by denys roman (denys_roman@yahoo.com) on 2018-08-29T22:51:25Z No. of bitstreams: 1 TA Denys - V29 de Julho.pdf: 2148232 bytes, checksum: 2f16875e1900c5b431bbcc02d057dd8e (MD5) / Rejected by Simone de Andrade Lopes Pires (simone.lopes@fgv.br), reason: Boa Tarde Denys, Recebemos seu trabalho na biblioteca digital, mas será necessário fazer alguns ajustes: Estou encaminhando por e-mail as alterações necessárias. Por favor, faça as alterações e submeta o trabalho novamente na biblioteca digital. Atenciosamente, Simone - SRA on 2018-08-30T20:48:27Z (GMT) / Submitted by denys roman (denys_roman@yahoo.com) on 2018-08-31T13:07:35Z No. of bitstreams: 1 TA Denys - V30 de Julho (2003)_corrigido.pdf: 2107428 bytes, checksum: 58f618ad30b083f6bf09aba20e9554c8 (MD5) / Approved for entry into archive by Simone de Andrade Lopes Pires (simone.lopes@fgv.br) on 2018-09-03T19:37:52Z (GMT) No. of bitstreams: 1 TA Denys - V30 de Julho (2003)_corrigido.pdf: 2107428 bytes, checksum: 58f618ad30b083f6bf09aba20e9554c8 (MD5) / Approved for entry into archive by Suzane Guimarães (suzane.guimaraes@fgv.br) on 2018-09-04T14:01:28Z (GMT) No. of bitstreams: 1 TA Denys - V30 de Julho (2003)_corrigido.pdf: 2107428 bytes, checksum: 58f618ad30b083f6bf09aba20e9554c8 (MD5) / Made available in DSpace on 2018-09-04T14:01:28Z (GMT). No. of bitstreams: 1 TA Denys - V30 de Julho (2003)_corrigido.pdf: 2107428 bytes, checksum: 58f618ad30b083f6bf09aba20e9554c8 (MD5) Previous issue date: 2018-08-02 / O presente trabalho visa explorar se as blockchains poderiam ser utilizadas para gerar maior confiança na asseguração de dados ESG – Environmental, Social and Corporate Governance (em português: Ambiental, Social e Governança Corporativa), visando apoiar o desenvolvimento da indústria do investimento sustentável. No desenvolvimento do trabalho, demonstramos o crescimento da indústria do investimento sustentável. Com a utilização de fatores ESG na avaliação de ativos, os registros desse fenômeno foram evidenciados tanto com dados de agentes do mercado de capitais quanto com dados da produção acadêmicocientífica. Também abordamos a possibilidade de fortalecimento da qualidade das informações ESG e sua asseguração externa para evitar potencial perda de valor das companhias em função de assimetria informacional. Para respondermos ao problema de pesquisa, foi realizado um estudo de caso que teve como unidade de análise a forma como a OriginalMy utiliza as blockchains para autenticação de dados. Esse estudo de caso foi precedido de etapas preliminares, em que foi desenvolvida uma prova de conceito para ampliar a familiaridade com a tecnologia e entrevistas com os asseguradores de informações ESG. O estudo apontou lacunas no processo de asseguração e que as características das blockchains permitem que a tecnologia sirva de base para soluções que necessitem garantir a autenticidade de dados. Dessa forma, podem apoiar o desenvolvimento da indústria de investimento sustentável baseado em dados mais confiáveis e robustos. / This paper aims to explore how blockchains can be used to generate greater confidence in ESG data – Environmental, Social and Corporate Governance, in order to support the development of the sustainable investment industry. We demonstrate the growth of the sustainable investment industry, with the use of ESG factors in the assets valuation, the records of this phenomenon were evidenced both with data from capital market agents and with data from academic-scientific production. We also discuss the possibility of strengthening the quality of ESG information and its external assurance to avoid potential loss of value of companies due to informational asymmetry. To respond the research problem, a case study was conducted that analyzed how OriginalMy uses the blockchains for data authentication. This case study was preceded by preliminary steps, in which a proof of concept was developed to increase familiarity with the technology and interviews with ESG information insurers. The study pointed to gaps in the assurance process and that the characteristics of blockchains allow the technology to serve as the basis for solutions that need to guarantee the authenticity of data. In this way, they can support the development of the sustainable investment industry based on more reliable and robust data.

This thesis presents an extension to Hyperledger Fabric, a private blockchain system, allowing historic transactions to be pruned without peer coordination. The feature is facilitated via pruning predicate functions, provided along any smart contracts a given system is desired to host. An evaluation of the extension demonstrates its impact, in terms of memory saved, for a specific asset delivery use case. It is concluded that the gains of pruning historic transactions from blockchain systems could yield significantly reduced storage requirements for some categories of applications, especially such with low transaction interdependency. It is also suggested that the deterministic consensus algorithms used by Hyperledger Fabric makes the transaction histories it may maintain not strictly required, meaning that the particular set of transactions that must survive pruning depend on what properties a blockchain is expected to maintain.

Smart contracts are self-executing electronic contracts. Amongst its deployed applications in the digital world is providing a decentralized and transparent method for executing transactions of cryptocurrencies on blockchains. Our thesis aims to investigate the mechanisms influencing execution of smart contracts across different blockchain networks when it comes to transactions of their native tokens. With a focus on the Ethereum, Avalanche, Cardano, Chainlink, and Binance blockchain technologies, an experiment is conducted which involves transferring native tokens on each of the blockchains to obtain results of the speed of each of the transfers and their respective transaction costs. The developed problem statement revolves around understanding the blockchain characteristics and smart contract implementations that contribute to these results. Properties of smart contracts and blockchain networks are established, which form the qualitative data components of our research. Further, we perform an analysis and evaluation of the quantitative results of our experiment to form a connection between each of the blockchains’ qualitative properties and their respective performance. Architecture, gas limit, gas price, and network congestion are identified as key determinants of gas fees and transaction costs. The choice of consensus mechanism, block time, and scalability solutions also play a significant role in transaction speed and time to finality. We believe our discoveries contribute to enhancing the implementation of smart contracts in the context of cryptocurrencies. / Smarta kontrakt är självutförande elektroniska kontrakt. Bland dess tillämpningar i den digitala världen ingår att tillhandahålla en decentraliserad och transparent metod för att utföra transaktioner av kryptovalutor på blockkedjor. Vår examensarbete syftar till att undersöka de mekanismer som påverkar utförandet av smarta kontrakt över olika blockkedjenätverk när det gäller transaktioner av deras valutor. Med fokus på Ethereum, Avalanche, Cardano, Chainlink och Binance blockkedjeteknologier genomförs ett experiment som innebär överföring av valutor på varje blockkedja för att erhålla resultat av hastigheten för varje överföring och deras respektive transaktionskostnader. Det utvecklade problemet kretsar kring förståelsen av blockkedjekaraktäristik och smarta kontraktsimplementeringar som bidrar till dessa resultat. Egenskaper hos smarta kontrakt och blockkedjenätverk fastställs, vilket utgör de kvalitativa datakomponenterna i vår forskning. Dessutom genomför vi en analys och utvärdering av de kvantitativa resultaten från vårt experiment för att skapa en koppling mellan varje blockkedjas kvalitativa egenskaper och deras respektive prestanda. Arkitektur, gasgräns, gaspris och nätverksöverbelastning identifieras som avgörande faktorerna för gasavgifter och transaktionskostnader. Valet av konsensusmekanism, blocktid och skalbarhetslösningar spelar också en betydande roll för transaktionshastighet och tidsmässig avslutning. Vi anser att våra upptäckter bidrar till att förbättra implementeringen av smarta kontrakt i sammanhanget av kryptovalutor.

La conception originale d’Internet n’a pas pris en compte les aspects de sécurité du réseau; l’objectif prioritaire était de faciliter le processus de communication. Par conséquent, de nombreux protocoles de l’infrastructure Internet exposent un ensemble de vulnérabilités. Ces dernières peuvent être exploitées par les attaquants afin de mener un ensemble d’attaques. Les attaques par déni de service distribué (Distributed Denial of Service ou DDoS) représentent une grande menace et l’une des attaques les plus dévastatrices causant des dommages collatéraux aux opérateurs de réseau ainsi qu’aux fournisseurs de services Internet. Les réseaux programmables, dits Software-Defined Networking (SDN), ont émergé comme un nouveau paradigme promettant de résoudre les limitations de l’architecture réseau actuelle en découplant le plan de contrôle du plan de données. D’une part, cette séparation permet un meilleur contrôle du réseau et apporte de nouvelles capacités pour mitiger les attaques par déni de service distribué. D’autre part, cette séparation introduit de nouveaux défis en matière de sécurité du plan de contrôle. L’enjeu de cette thèse est double. D’une part, étudier et explorer l’apport de SDN à la sécurité afin de concevoir des solutions efficaces qui vont mitiger plusieurs vecteurs d’attaques. D’autre part, protéger SDN contre ces attaques. À travers ce travail de recherche, nous contribuons à la mitigation des attaques par déni de service distribué sur deux niveaux (intra-domaine et inter-domaine), et nous contribuons au renforcement de l’aspect sécurité dans les réseaux programmables. / The original design of Internet did not take into consideration security aspects of the network; the priority was to facilitate the process of communication. Therefore, many of the protocols that are part of the Internet infrastructure expose a set of vulnerabilities that can be exploited by attackers to carry out a set of attacks. Distributed Denial-of-Service (DDoS) represents a big threat and one of the most devastating and destructive attacks plaguing network operators and Internet service providers (ISPs) in a stealthy way. Software defined networks (SDN), an emerging technology, promise to solve the limitations of the conventional network architecture by decoupling the control plane from the data plane. On one hand, the separation of the control plane from the data plane allows for more control over the network and brings new capabilities to deal with DDoS attacks. On the other hand, this separation introduces new challenges regarding the security of the control plane. This thesis aims to deal with various types of attacks including DDoS attacks while protecting the resources of the control plane. In this thesis, we contribute to the mitigation of both intra-domain and inter-domain DDoS attacks, and to the reinforcement of security aspects in SDN.