PDFS: Practical Data Feed Service for Smart Contracts

Smart contracts allow untrusting parties to arrange agreements encoded as code deployed on a blockchain platform. To release their potential, it is necessary to connect the contracts with the outside world, such that they can understand and use information from other infrastructures. However, there are many challenges associated with realizing such a system, and despite the existence of many proposals, no solution is secure, provides easily-parsable data, introduces small overheads, and is easy to deploy.