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Simply put, a smart contract is a distributed trusted program that runs on a blockchain network . It , it is the business logic of a blockchain application [2]. It is distributed because all the network participants not only have a copy of the smart contract, but they also execute the smart contract. It is trusted because once the participants execute the smart contract, they must have the same outcome and come to consensus. Once the criteria on the blockchain network is met, then its code defined in the smart contract will automatically execute, applying any business logic contained as predifined built-in rules.
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