Privacy Preservation & Security Solutions in Blockchain Network

Blockchain has seen exponential progress over the past few years, and today its usage extends well beyond cryptocurrencies. Its features, including openness, transparency, secure communication, difficult falsification, and multi-consensus, have made it one of the most valuable technology in the world. In most open blockchain platforms, any node can access the data on the blockchain, which leads to a potential risk of personal information leakage. So the issue of blockchain privacy and security is particularly prominent and has become an important research topic in the field of blockchain. This dissertation mainly summarizes my research on blockchain privacy and security protection issues throughout recent years. We first summarize the security and privacy vulnerabilities in the mining pools of traditional bitcoin networks and some possible protection measures. We then propose a new type of attack: coin hopping attack, in the case of multiple blockchains under an IoT environment. This attack is only feasible in blockchain-based IoT scenarios, and can significantly reduce the operational efficiency of the entire blockchain network in the long run. We demonstrate the feasibility of this attack by theoretical analysis of four different attack models and propose two possible solutions. We also propose an innovative hybrid blockchain crowdsourcing platform solution to settle the performance bottlenecks and various challenges caused by privacy, scalability, and verification efficiency problems of current blockchain-based crowdsourcing systems. We offer flexible task-based permission control and a zero-knowledge proof mechanism in the implementation of smart contracts to flexibly obtain different levels of privacy protection. By performing several tests on Ethereum and Hyperledger Fabric, EoS.io blockchains, the performance of the proposed platform consensus under different transaction volumes is verified. At last, we also propose further investigation on the topics of the privacy issues when combining AI with blockchain and propose some defense strategies

TheChain: a fast, secure and parallel treatment of transactions

The Smart Distributed Ledger (aka blockchain) has attracted much attention in recent years. According to the European Parliament, this technology has the potential to change the lives of many people. The blockchain is a data structure built upon a hashed function in a distributed network, enabled by an incentive mechanism to discourage malicious nodes from participation. The consensus is at the core of the blockchain technology, and is driven by information embedded into a data structure that takes many forms such as linear, tree, and graph chains. The found related information will be subject to various validation incentives among the miners, such as proof of stake and proof of work. However, all the existing solutions suffer from a heavy state transition before dealing with the problem of a validation mechanism which suffers from resource consumption, monopoly or attacks. This work raises the following question: "Why is there a need for consensus where all participants can make a quick and correct decision?", and underlines the fact that sometimes ledger is subject to maintenance from regional parties in the data that leads to partial territories and eliminates monopoly, which is the hurdle to eliminating the trusted party. The validity of the blockchain transaction comes from the related information scattered above the data structure, and the authenticity lies in the digital signature. The aim is to switch from a validator based on incentives to a broadcaster governed by an unsupervised clustering algorithm, and the integrity does lie in the intersection among regions. However, the data structure takes advantage of the Petri network regarding its suitability. Building the entire ledger in the Petri network model will allow parallel processing of the transactions and securing of the total order between the participants on the memory reference layer. Moreover, it takes account of validation criteria quickly and safely before adding the new transaction list using the graph reachability

Blockchain in Energy Communities, A proof of concept

This report aims at exploring the use of the distributed ledger paradigm to incentive the participation of the citizen to a truly free, open and interoperable energy market, producing a feasibility study and a first demo testbed, taking also into consideration privacy, cybersecurity and big-data issues of the smart-home in the Energy market context. This study is intended to support point 4.1, 4.2 and 4.3 of the DSM (COM(2015)192) and point 2.2 of the Energy Union package (COM(2015)80.JRC.E.3-Cyber and Digital Citizens' Securit

Security Threats Classification in Blockchains

Blockchain, the foundation of Bitcoin, has become one of the most popular technologies to create and manage digital transactions recently. It serves as an immutable ledger which allows transactions take place in a decentralized manner. This expeditiously evolving technology has the potential to lead to a shift in thinking about digital transactions in multiple sectors including, Internet of Things, healthcare, energy, supply chain, manufacturing, cybersecurity and principally financial services. However, this emerging technology is still in its infancy. Despite the huge opportunities blockchain offers, it suffers from challenges and limitation such as scalability, security, and privacy, compliance, and governance issues that have not yet been thoroughly explored and addressed. Although there are some studies on the security and privacy issues of the blockchain, they lack a systematic examination of the security of blockchain systems. This research conducted a systematic survey of the security threats to the blockchain systems and reviewed the existing vulnerabilities in the Blockchain. These vulnerabilities lead to the execution of the various security threats to the normal functionality of the Blockchain platforms. Moreover, the study provides a case-study for each attack by examining the popular blockchain systems and also reviews possible countermeasures which could be used in the development of various blockchain systems. Furthermore, this study developed taxonomies that classified the security threats and attacks based on the blockchain abstract layers, blockchain primary processes and primary business users. This would assist the developers and businesses to be attentive to the existing threats in different areas of the blockchain-based platforms and plan accordingly to mitigate risk. Finally, summarized the critical open challenges, and suggest future research directions

Incentive Analysis of Blockchain Technology

Blockchain technology was invented in the Bitcoin whitepaper released in 2008. Since then, several decentralized cryptocurrencies and applications have become mainstream. There has been an immense amount of engineering effort put into developing blockchain networks. Relatively few projects backed by blockchain technology have succeeded and maintained a large community of developers, users, and customers, while many popular projects with billions of dollars in funding and market capitalizations have turned out to be complete scams. This thesis discusses the technological innovations introduced in the Bitcoin whitepaper and the following work of the last fifteen years that has enabled blockchain technology. A complete implementation of a blockchain network and cryptocurrency based on first principles is presented in order to illustrate the design and technical choices that have to be made while implementing a blockchain. To understand the incentives that drive the adoption of blockchain technology, two successful blockchain projects, Crypto Kitties, which is a Non-Fungible Token (NFT) project based on the ERC-721 specification and Helium, are analysed as case studies. These case studies first examine how these projects leveraged blockchain technology from a technical standpoint, followed by a discussion of the incentives that were built into the projects, which allowed millions of users to participate in these networks and create value. The economic incentives created by Crypto-assets which are a combination of cryptocurrency and tokens, are explored. The purpose of this thesis is to provide an informational overview of the incentives and technical choices driving the development and adoption of blockchain technology

A Survey on Consensus Mechanisms and Mining Strategy Management in Blockchain Networks

© 2013 IEEE. The past decade has witnessed the rapid evolution in blockchain technologies, which has attracted tremendous interests from both the research communities and industries. The blockchain network was originated from the Internet financial sector as a decentralized, immutable ledger system for transactional data ordering. Nowadays, it is envisioned as a powerful backbone/framework for decentralized data processing and data-driven self-organization in flat, open-access networks. In particular, the plausible characteristics of decentralization, immutability, and self-organization are primarily owing to the unique decentralized consensus mechanisms introduced by blockchain networks. This survey is motivated by the lack of a comprehensive literature review on the development of decentralized consensus mechanisms in blockchain networks. In this paper, we provide a systematic vision of the organization of blockchain networks. By emphasizing the unique characteristics of decentralized consensus in blockchain networks, our in-depth review of the state-of-the-art consensus protocols is focused on both the perspective of distributed consensus system design and the perspective of incentive mechanism design. From a game-theoretic point of view, we also provide a thorough review of the strategy adopted for self-organization by the individual nodes in the blockchain backbone networks. Consequently, we provide a comprehensive survey of the emerging applications of blockchain networks in a broad area of telecommunication. We highlight our special interest in how the consensus mechanisms impact these applications. Finally, we discuss several open issues in the protocol design for blockchain consensus and the related potential research directions

Internet of Things From Hype to Reality

The Internet of Things (IoT) has gained significant mindshare, let alone attention, in academia and the industry especially over the past few years. The reasons behind this interest are the potential capabilities that IoT promises to offer. On the personal level, it paints a picture of a future world where all the things in our ambient environment are connected to the Internet and seamlessly communicate with each other to operate intelligently. The ultimate goal is to enable objects around us to efficiently sense our surroundings, inexpensively communicate, and ultimately create a better environment for us: one where everyday objects act based on what we need and like without explicit instructions