information Review Understanding the Blockchain Oracle Problem: A Call for Action Giulio Caldarelli Department of Business Administration, University of Verona, 37129 Verona, Italy;
[email protected] Received: 12 September 2020; Accepted: 28 October 2020; Published: 29 October 2020 Abstract: Scarce and niche in the literature just a few years ago, the blockchain topic is now the main subject in conference papers and books. However, the hype generated by the technology and its potential implications for real-world applications is flawed by many misconceptions about how it works and how it is implemented, creating faulty thinking or overly optimistic expectations. Too often, characteristics such as immutability, transparency, and censorship resistance, which mainly belong to the bitcoin blockchain, are sought in regular blockchains, whose potential is barely comparable. Furthermore, critical aspects such as oracles and their role in smart contracts receive few literature contributions, leaving results and theoretical implications highly questionable. This literature review of the latest papers in the field aims to give clarity to the blockchain oracle problem by discussing its effects in some of the most promising real-world applications. The analysis supports the view that the more trusted a system is, the less the oracle problem impacts. Keywords: blockchain; smart contracts; oracles 1. Introduction “Is the blockchain the greatest technological innovation since the internet ::: or the greatest load of hype ever raged around the history of technology? ::: Both” (Andreas Antonopoulos). Blockchain’s primary innovation is that it allows business partners to transfer digital assets without the need for a centralized third party [1]. However, as blockchain can execute only simple transactions, “smart contracts” are necessary to settle the terms of an agreement [2,3].