The Merits of a Decentralized Pollution-Monitoring System Based on Distributed Ledger Technology

Pollution-monitoring systems (PMSs) are used worldwide to sense environmental changes, such as air quality conditions or temperature increases, and to monitor compliance with regulations. However, organizations manage the environmental data collected by such PMSs in a centralized manner, which is why recorded environmental data are vulnerable to manipulation. Moreover, the analysis of pollution data often lacks transparency to outsiders, which may lead to wrong decisions regarding environmental regulations. To address these challenges, we propose a software design for PMSs based on distributed ledger technology (DLT) and the long-range (LoRa) protocol for flexible, transparent, and energy-efficient environment monitoring and data management. To design the PMS, we conducted a comprehensive requirements analysis for PMSs. We benchmarked different consensus mechanisms (e.g., BFT-SMaRt and Raft) and digital signature schemes (e.g., ECDSA and EdDSA) to adequately design the PMS and fulfill the identified requirements

What is a Blockchain? A Definition to Clarify the Role of the Blockchain in the Internet of Things

The use of the term blockchain is documented for disparate projects, from cryptocurrencies to applications for the Internet of Things (IoT), and many more. The concept of blockchain appears therefore blurred, as it is hard to believe that the same technology can empower applications that have extremely different requirements and exhibit dissimilar performance and security. This position paper elaborates on the theory of distributed systems to advance a clear definition of blockchain that allows us to clarify its role in the IoT. This definition inextricably binds together three elements that, as a whole, provide the blockchain with those unique features that distinguish it from other distributed ledger technologies: immutability, transparency and anonimity. We note however that immutability comes at the expense of remarkable resource consumption, transparency demands no confidentiality and anonymity prevents user identification and registration. This is in stark contrast to the requirements of most IoT applications that are made up of resource constrained devices, whose data need to be kept confidential and users to be clearly known. Building on the proposed definition, we derive new guidelines for selecting the proper distributed ledger technology depending on application requirements and trust models, identifying common pitfalls leading to improper applications of the blockchain. We finally indicate a feasible role of the blockchain for the IoT: myriads of local, IoT transactions can be aggregated off-chain and then be successfully recorded on an external blockchain as a means of public accountability when required

Blockchain Oracles

Plokiahelatehnoloogia on osutunud paljude tööstusharude potentsiaalseks lammutajaks ning on saanud eraldiseisvate üksuste jaoks turvalise ja detsentraliseeritud toimimise võimaldajaks. Sellest hoolimata ei ole plokiahelatehnoloogia iseenesest väliste andmeallikatega otseselt seotud. Vajalikke väliseid andmeid vahendatakse oraaklite abil. Selle magistritöö eesmärk on uurida seoseid plokiahela võrkude ja oraaklite vahel ning töötada välja raamistik, mis aitab plokiahela arendajaid ja otsuste langetajaid nende plokiahela projektides millestki juhinduda. Mõnedes olemasolevates oraakliprojektides on kirjeldatud sarnaseid püüdluseid, kuid seni pole nende autorid süstemaatiliste ülevaadeteni jõudnud. Lõputöös esitatud raamistik on välja töötatud olemasolevate oraaklitega seotud plokiahela projektide süstemaatilise kirjanduse ülevaate põhjal. See hõlmab selliseid komponente nagu oraaklite poolt kogutud informatsiooni tüübid, plokiahelavõrgud, millega nad suhtlevad, ning ka oraaklite ja andmeallika vahelise suhtluse krüptimine. Lisaks mängib plokiahela oraakli projektides olulist rolli ka oraaklite otsuste tegemine, mis kajastab teabe edastamist oraaklile, nende andmete kontrollimist ja meetodeid, kuidas oraakleid integreeritakse plokiahela võrkudega. Läbivaatamise tulemused näitavad, et plokiahela oraaklid on keerulised lahendused, mis hõlmavad paljusid komponente ja aspekte. Need võivad olla immateriaalsed või materiaalsed ning edastada andmeid vastavalt veebist või anduriseadmetest. Oraakleid saab kasutada igat tüüpi plokiahela võrkudes ja integreerida erinevates formaatides, sealhulgas nutikates lepinguliidestes, või otse teiste plokiahela-sõlmedega. Neid saab otsustusprotsessides tsentraliseerida või detsentraliseerida ja nad suudavad kasutada andmete õigsuse üle otsustamiseks mitmesuguseid olemasolevaid nõuandemehhanisme või usaldada lihtsalt välist andmepakkujat. Need uurimise tulemused aitavad plokiahela arendajatel demüstifitseerida oraaklite potentsiaalset kasutamist või rakendamist oma plokiahela projektides ning aitavad ületada lõhet plokiahela virtuaalse maailma ja väliste keskkondade vahel.Blockchain technology has emerged as a potential disruptor of multiple industries and became an enabler for separate entities to trans-act in a secure and decentralized manner. Nevertheless, the blockchain technology in itself does not directly interact with the external data sources. External data, that is needed, is transferred by means of oracles. The research goal of this thesis is to explore the relationship between blockchain networks and oracles and develop a framework to help guide blockchain developers and decision makers in their blockchain projects. Few of the existing oracle projects have described similar efforts in their papers, but no systematic review has been made by authors. The framework, presented in the thesis, is developed based on Systematic Literature Review of existing blockchain projects involving oracles. It includes components such as type of information oracles collect, blockchain networks with which they interact as well as encryption of communication between the oracles and the data source. Additionally, oracle decision making, which captures how the information is passed to the oracle, along with the verification of that data and methods of integration of oracles with blockchain networks, play an important role in blockchain oracle projects. The results of the review demonstrate that blockchain oracles are complex solutions involving multiple components and aspects. They can be intangible or tangible and transport data from web or sensor devices respectively. Oracles can be used in all types of blockchain networks and integrated in different formats including custom smart contract interfaces or directly with blockchain nodes. They can be centralized or decentralized in terms of decision making and utilize various existing consensus mechanisms to decide on correctness of the data or simply trust the external data provider. These findings will help the blockchain developers demystify the potential usage or implementation of oracles in their blockchain projects and help bridge the gap between the virtual world of blockchain and the external environments

The Theory and Application of Privacy-preserving Computation

Privacy is a growing concern in the digital world as more information becomes digital every day. Often the implications of how this information could be exploited for nefarious purposes are not explored until after the fact. The public is becoming more concerned about this. This dissertation introduces a new paradigm for tackling the problem, namely, transferable multiparty computation (T-MPC). T-MPC builds upon existing multiparty computation work yet allows some additional flexibility in the set of participants. T-MPC is orders of magnitude more efficient for certain applications. This greatly increases the scalability of the sizes of networks supported for privacy-preserving computation

A patient agent controlled customized blockchain based framework for internet of things

Although Blockchain implementations have emerged as revolutionary technologies for various industrial applications including cryptocurrencies, they have not been widely deployed to store data streaming from sensors to remote servers in architectures known as Internet of Things. New Blockchain for the Internet of Things models promise secure solutions for eHealth, smart cities, and other applications. These models pave the way for continuous monitoring of patient’s physiological signs with wearable sensors to augment traditional medical practice without recourse to storing data with a trusted authority. However, existing Blockchain algorithms cannot accommodate the huge volumes, security, and privacy requirements of health data. In this thesis, our first contribution is an End-to-End secure eHealth architecture that introduces an intelligent Patient Centric Agent. The Patient Centric Agent executing on dedicated hardware manages the storage and access of streams of sensors generated health data, into a customized Blockchain and other less secure repositories. As IoT devices cannot host Blockchain technology due to their limited memory, power, and computational resources, the Patient Centric Agent coordinates and communicates with a private customized Blockchain on behalf of the wearable devices. While the adoption of a Patient Centric Agent offers solutions for addressing continuous monitoring of patients’ health, dealing with storage, data privacy and network security issues, the architecture is vulnerable to Denial of Services(DoS) and single point of failure attacks. To address this issue, we advance a second contribution; a decentralised eHealth system in which the Patient Centric Agent is replicated at three levels: Sensing Layer, NEAR Processing Layer and FAR Processing Layer. The functionalities of the Patient Centric Agent are customized to manage the tasks of the three levels. Simulations confirm protection of the architecture against DoS attacks. Few patients require all their health data to be stored in Blockchain repositories but instead need to select an appropriate storage medium for each chunk of data by matching their personal needs and preferences with features of candidate storage mediums. Motivated by this context, we advance third contribution; a recommendation model for health data storage that can accommodate patient preferences and make storage decisions rapidly, in real-time, even with streamed data. The mapping between health data features and characteristics of each repository is learned using machine learning. The Blockchain’s capacity to make transactions and store records without central oversight enables its application for IoT networks outside health such as underwater IoT networks where the unattended nature of the nodes threatens their security and privacy. However, underwater IoT differs from ground IoT as acoustics signals are the communication media leading to high propagation delays, high error rates exacerbated by turbulent water currents. Our fourth contribution is a customized Blockchain leveraged framework with the model of Patient-Centric Agent renamed as Smart Agent for securely monitoring underwater IoT. Finally, the smart Agent has been investigated in developing an IoT smart home or cities monitoring framework. The key algorithms underpinning to each contribution have been implemented and analysed using simulators.Doctor of Philosoph