The oracle's business model is to execute off-chain (off-blockchain) queries and return them to the contract in exchange for a fee, which the contract pays by asking oracles for off-chain data.

So how do we create a decentralized oracle? The model is as follows: a contract should ask several oracles to execute the same query, get results from each oracle, and then determine the correct answer on its own based on multiple results (answers…

External data to the smart contract (from outside the blockchain) can be provided only, as parameters (arguments) of its call. Oracles are software running outside the blockchain, which listens for "requests" by smart contracts for external data,…