Oracle machines are abstract computers that can solve decision problems by executing complex mathematical formulas and act as an impartial untampered third-party agent. In their blockchain use, the oracle’s role is to filter, verify and harmonize real-world data so that it can safely integrate into the blockchain and be used, for example, in the execution of smart contracts. When equipped with machine-learning functionality, oracles can help rapidly resolve contradicting inputs or data anomalies prior to their entry on the blockchain. The blockchain does not store the raw environmental data from IoT sensors, but it can store its hashes, and the single record with agreed consensus.