In 1997, Nick Szabo introduced the idea of smart contract as a safe instrument of agreement. He explained his idea in a simplified form using vending machines as a metaphor. As he stated: “…the machine takes in coins, and via a simple mechanism, (…), dispense change and product according to the displayed price. The vending machine is a contract with bearer: anybody with coins can participate in an exchange with the vendor.” To put it in an actualized context, smart contracts are digital applications that store, verify and execute rules without a trusted authority. The first platform, who realised smart contracts in practice and provided a platform for the technology to grow was Ethereum, and ever since this is the biggest platform for individuals to use blockchain system in such ways.