Emancipation of the bitcoin outcasts: addressing overlooked elements of the bitcoin network for improving security and efficiency

Abstract

During the last decade, cryptocurrencies have revolutionized the financial industry. In these systems, participants communicate by means of a peer-to-peer protocol. Today, many of such protocols take Bitcoin as a reference model, making its study particularly important.

This thesis explores some important aspects of the Bitcoin network, related to its security and efficiency, that received limited coverage in research. Firstly, properties of the Testnet network are explored, showing they can be exploited for malicious activities. Secondly, security aspects of an open network topology are studied, arguing against the current obfuscated approach, and designing a viable monitoring system. Then, unreachable nodes are considered, showing their relevance in the network, and proposing changes to the protocol that improve efficiency and security. Finally, a new transaction relay protocol is proposed, which improves anonymity.

The results obtained show that the aspects we analyze are not sufficiently covered in research and deserve more deep investigation.

En l'última decada, les criptomonedes han revolucionat el món de les finançes globals. En aquestes xarxes, els participants comuniquen a través de un protocol peer-to-peer. Molts d'aquests protocols fan servir Bitcoin com punt de referencia, fent el seu estudi especialment important.

Aquesta tesi explora alguns aspectes rellevants per la seguretat i eficiencia de la xarxa Bitcoin que han estat poc endreçats a la recerca. En primer lloc, analitzem la xarxa Testnet, mostrant com les seves proprietats poden ser explotades per activitats malicioses. A continuació, estudiem la seguretat de la topologia de la xarxa Bitcoin, promovent la seva accessibilitat i dissenyant un sistema de monitoratge. Finalment, mostrem la importància dels nodes \textit{unreachable} a la xarxa i dissenyem nous protocols de propagació per protegir l'anonimitat de les transaccions.

Els resultats obtinguts demonstren que els aspectes analitzats no reben suficient atenció a la recerca i mereixen ser investigats més a fons.