Resumen de Towards a better understanding of bitcoin: from system analyses to new protocol designs
Sergi Delgado Segura
Bitcoin has kicked off one of the biggest paradigm shifts of the last century regarding how we understand and use money. The birth of criptocurrencies lays the foundations of a new financial system, where the need of trusted third parties, or central authorities, has been replaced by cryptography and an open flow of information between all the actors of the system. By sharing all the information regarding the operations of the system, all users can eventually agree in a distributed ledger, known as blockchain. Such a paradigm shift, however, poses some threads that, if not properly handled, may compromise the security of the system.
In this thesis we have studied two of the core components of Bitcoin: its P2P network, and the set of unspent Bitcoins. Such analysis aimed to spot the strengths and weaknesses of the system in order to design solutions for them. The outcomes of our analyses have been, on the one side, characterizing the cryptocurrency P2P networks and, on the other side, spotting one of the current Bitcoin scalability problems: the unprofitable coins.
Moreover, after analysing the system and obtaining a deep understanding of it, the thesis has focused on designing protocols to extend Bitcoin’s functionality in different payment scenarios. First, we have designed a solution to reduce the likelihood of a merchant of being deceived when accepting zero-confirmation transactions. Finally, we have designed a fair protocol for data trading using Bitcoin, where the exchange between data and coins is performed atomically.
