Blockchain oracles for document certification: A case study

The use of blockchain oracles is becoming increasingly widespread as it responds to the problem of providing the blockchain with external data automatically. In this paper, we focus on the use of blockchain oracles for the certification of articulated data. In particular, we show how it is possible to design and implement a DApp capable of providing documents on request without these data permanently residing on the blockchain. We present a case study of the on-demand provision of university curriculum, fully managed via a blockchain oracle. In this system, the smart contract will not record data permanently but only for the time necessary for its use. The system is intended to allow a user to request and obtain data only about herself. The paper also presents a classification of the types of blockchain oracles and their most common applications. The case study will be presented as blockchain-oriented software, and in terms of architecture and dynamics using UML diagrams, the benefits and drawbacks of the approach are discussed.