The blockchain technology. Analysis and applications.

This thesis concerns the study of the blockchain-based cryptocurrencies, and can be framed in the field of the software engineering. In particular, it involves the study of the blockchain technology, the engineering aspects related to blockchain-based software development, and case of studies in applicative scenarios. The first part of the thesis begins with the empirical study of Bitcoin transaction data. Studying data stored inside the blockchain means studying the network dimension evolution, the users’ interactions and the richness distribution. The study concerns the modelling and the analytic study of the entire transaction set, during the period between the first Bitcoin years (2009-2012). The modelling process passes through the creation of a bipartite graph, specifically a Petri net, to exploit the properties of a well structured algebraic formalism. Results show interesting properties of the blockchain data. Addresses usage statistics and the number of interconnections follow power law distributions. The model allows a higher level representation, that takes into account the real usage of addresses and transactions. Then, the thesis directs the research focus on the study of blockchain challenges and opportunities if used in place of centralized banking systems. This study discusses the necessity of a sustainable development, that can pass through the global financial infrastructure optimization, using more efficient systems than at present. Many banks are currently focusing on blockchain technology to promote economic growth and accelerate the green technologies development. Furthermore, the chapter describes the real performances of the Bitcoin system, in terms of its efficiency. After collecting data about mining costs and computing specific regression functions, it shows the results in terms of its efficiency, defining three quantities: “economic efficiency”, “operational efficiency”, and “efficient service”. The obtained results show that by overcoming the disadvantages of the Bitcoin system, and of blockchain technology, we could be able to handle financial processes in a more efficient way than under the current system. The second part of the thesis opens with a discussion of the need of a new software engineering branch, specific for the blockchain technology. The study describes the key elements that characterize blockchain-based software, and define the Blockchain-Oriented Software Engineering (BOSE) environments. Blockchain-oriented software projects can be distinguished from other software projects due to the nature of the technology used. They need special attention, especially in terms of security and reliability issues, architecture specifications, metrics and modeling language definition. In fact, there are not enough guidelines that properly drive the use of the blockchain. Then, the thesis offers two cases of studies on the blockchain technology in application scenarios. The first concerns the use of the blockchain to create a smart city system that allows citizens to give, through mobile smart objects, some environmental measurements and that creates an aviable geographical located dataset. The blockchain allows citizens to collaborate using a decentralized system and make the data always available, immutable and certified. The second case of study concerns the description and the definition of key elements of a decentralized energy market based on blockchain. This system uses the blockchain to handle deals and record energy purchases. The purpose is to make the citizen free to buy and sell electricity to the best bidder and to optimize his profits and save. The thesis concludes by summarizing results and providing final considerations.