Oracles • Why do we need oracles? - All parties to an agreement must be able to independently arrive at the same result for a given transaction - We cannot ensure that external services will always return the same answer - We need trusted agents that can attest to certain facts by signing transactions that contain them • What can oracles do? - Act as a trusted source of data - Respond to defined queries - Sign data within a transaction - Act as a definitive model / valuation service - Act as a scheduler or notification service UNRESTRICTED 74