Oracles in Blockchain Architectures: A Literature Review on Their Implementation in Complex Multi-organizational Processes

Blockchain is an innovative approach for recording and sharing data among storage nodes. Each node replicates an exact copy of the blockchain, but blockchains cannot trust external information without validation from their own nodes. To ensure integrity and security, information in the blockchain must come from trusted sources and be validated by nodes. Oracles, conceived during Bitcoin's development, allows the implementation of complex processes that use external information to blockchains. However, using oracles poses challenges in accuracy, reliability, and timely updates. This literature review study examines oracle characteristics, their impact on trust in external information, their application in complex organizational processes, and proposed solutions. PRISMA guidelines were followed, selecting relevant articles for quality assessment. Findings highlight the need for oracles from trusted sources, decentralized architectures, and data validation. The study concludes that proper use of oracles and development of specific techniques and protocols are crucial for data integrity and security in blockchains.