Τεχνολογία Blockchain και ανάπτυξη έξυπνων συμβολαίων για την αγοραπωλησία μοναδικών τεκμηρίων

Abstract

Blockchain technology was first used by Shatoshi Nakamoto in 2009 to create the bitcoin platform, a digital cryptocurrency that is still considered the most successful cryptocurrency in the world today. The bitcoin platform is mainly used for the execution of digital financial transactions between strangers without the existence of an entity that mediates for their valid completion. The creation of bitcoin has radically changed the way online transactions are done. Many other forms of cryptocurrencies developed after bitcoin but most followed a similar principle of operation to bitcoin without offering anything different. But blockchain technology has continued to evolve and as a result the range of applications in which it is used is constantly expanding. Now this technology is used in applications of industry, economy and simple everyday life of a person because of the security and validity it provides. In 2013, VitalikButerin created the Ethereum blockchain, a platform that supports the creation of distributed applications known as DApps (decentralized applications). Distributed applications developed in the ethereum blockchain are not limited to financial transactions such as bitcoin because the ethereum platform allows the creation of various types of applications using logic stored within the network, the well-known smart contracts. Smart contracts are code files that are executed with absoluteness and determinism, with the result that their functionality is universal. Possible applications that are based on the functionality of a smart contract and do not involve financial transactions are the securing of rights, logistics or even applications that provide a form of hierarchy. This thesis was created in order to highlight the possibilities and limits of smart contracts as well as problems that may exist during their development and after migration. The application is developed in a local ethereum blockchain network and deals with the creation of digital tokens. Digital tokens are known in the ethereum community as intangible assets that can take the form of cryptocurrencies or have the property of uniqueness, resulting in them being distinct and acquiring specific characteristics. In this application, both tokens are developed, resulting in the creation of a digital market with unique tokens that can be created, bought and sold in exchange for tokens that resemble a cryptocurrency. In any case, the common factor for the creation of tokens is ownability, which means that a token, whether it is unique or serves as a cryptocurrency, belongs to a specific user where he has all the advantages that this item provides him and no other user has them.