Blockchain Technology: A Framework for Endless Applications

Over the last decade, blockchain technology has evolved from being a peer-to-peer implementation of digital currency into a framework for numerous applications. That is, blockchain is widely recognized as the technology behind cryptocurrencies, such as bitcoin, but recent research indicates that it can be exploited way more than that. Among the most notable characteristics of the blockchain technology are system decentralization, data immutability, transaction transparency, and user privacy. Thus, it becomes apparent that it can significantly benefit many consumer applications, where trust and security are crucial aspects of the implementation. In this paper, we review and present, in a tutorial manner, blockchain's fundamental postulates and characteristics, and we introduce a novel point of view, where we visualize a layered representation of the blockchain infrastructure, so as to analyze it as a framework. Thinking of blockchain technology as a framework may assist consumers to better understand its capabilities and limitations. In addition, we review emerging blockchain-based applications that span across many different scientific fields. We also discuss the relative merits and restrictions. Namely, we have identified applications in finance, smart contracts, Internet of Things, e-voting systems, storage and data protection, reputation systems, healthcare, and transportation, indicating that the blockchain technology is becoming a framework for endless applications.